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COPYRIGHT DEPOSHV 


:) those customers 
; are always one- 
ready to ship. 


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hey are also sub¬ 
obtain the latest 
s. When orders 


letter should al- 
must be accom- 
portation charges 

both ways. Remittances (always to the order of Fraser & Chalmers) should 
be made by the usual commercial methods, Bills of Exchange, Drafts, Checks, 
Postal or Money Orders. We are not responsible for currency lost through 
the mail. 

SHIPMENT 


State whether shipment is desired by freight or express, and if there is any 
preference, name the route. We are always glad to give customers our best 
information as to freight charges. Our prices are usually quoted F. 0. B. 
Chicago, unless specified F. 0. B. at agencies or nearer handling points. In the 
absence of special arrangements a moderate charge for casing and cartage will 
invariably be made, and there will be no allowance for the return of packing 
cases. We exercise great care in packing, and obtain receipts from the for¬ 
warders of shipments “in good condition”. If goods are damaged in transit 
make prompt claim upon the Shipping Railroad or Express Company, and 
write us the particulars. While not ourselves responsible, we are desirous of 
having the claims of our customers equitably adjusted. 


CODE AND CATALOGUES 

Old catalogues are displaced by new issues, and when this is done, while 
they bear the same number as old catalogues, they will be known as first, 
second, third and fourth editions, etc., and the last edition is always considered 
to take the place of a catalogue of an earlier edition bearing the same number. 
Designs illustrated in catalogues are at any time subject to modification in de¬ 
tails. It should be borne in mind that deviations from standard sizes and 
types of machinery usually cause delay and additional expense. 

Cable Address " Vanner”, Chicago, or “Vanner”, London. 

Codes used: A. B C. 4*h London Edition, Moreing and Neal and Bedford McNeill. 

All communications should be addressed to Company. 












Roasting 

Smelting 

Refining 


CAi ALOGUE No. 3 

4th Edition, June, 1899 




METHODS 

MACHINERY 



Copyrighted 1899, by Fraser & Chalmers 
Chicago, III. 


L 





T 8 

38145 ,'KV 

FRASER & CHALMERS 


Manufacturers of 


MINING MACHINERY 




GENERAL OFFICES 

CHICAGO, ILL., U. S. A., 12th St. and Washtenaw Ave. 
LONDON, ENG., ... 43 Threadneedle St. 


WORKS 

CHICAGO, ILL., U. S. A., 12th St. and Washtenaw Ave. 
ENGLAND,.Erith, Kent 

SALES OFFICES 

CHICAGO NEW YORK 


Marquette Bldg., Dearborn and Adams Sts. 
Suite 1426=7-8=9, 14th Floor 


80 Broadway 


LC control Number 






tinp86 025488 



TABLE OF CONTENTS 


Page 

Introductory • 4 

SAMPLING ...... 6 

Sampling Machines ..... 7 

Sample Grinders . . . . .15 

Sampling Plants ..... 20 

ROASTING . . . . . .23 

Oxidizing Roasting .... 24 

Chloridizing Roasting .... 27 

Sulphate Roasting . . . . .27 

ROASTING FURNACES . . . .51 

Reverberatory Furnace . . . . 71 

Reverberatory (slagging) . . . .32 

Brown’s Roasting Furnace .... 36 

Bruckner Roaster . . . .44 

White-Howell Roaster . . . .49 

Stetefeldt Roasting Furnace . . .52 

Muffle Furnace ..... 53 

SMELTING ...... 55 

General Remarks ..... 56 

Pyritic Smelting ..... 59 

Iron Matte Smelting .... 60 

System for Heating Blast .... 60 

BLAST FURNACES ..... 65 

Blast Furnaces for Lead Ores ... 65 

Blast Furnaces for Copper Ores . . . 71 

WATER JACKETS ..... 80 

FURNACE CAPACITY .... 90 

BLAST FURNACE ACCESSORIES ... 92 

LARGE SMELTING PLANTS . . . hi 

SMALL SMELTING PLANTS . . .113 

GENERAL SMELTING OPERATIONS . . 117 

COST OF SMELTING . . . .118 

REVERBERATORY SMELTING FURNACES . 119 

DISPOSITION OF SLAG . . . .122 

SEPARATION OF MATTE FROM SLAG . . 129 

BRICKING OF FINE ORE . . . 131 

COPPER CONVERTING .... 134 

COPPER REFINING . . . -155 

CUPELLATION ..... 160 

LEAD REFINING ..... 165 


r * 









INTRODUCTORY 


We take pleasure in presenting to our patrons and 
the mining public this Fourth Edition of our No. 3 
Catalogue devoted to illustrated descriptions of the 
machinery which modern practice has found best suited 
for the purpose of extracting gold, silver, lead and 
copper from ores by igneous processes. 

Since the earlier days of mining in this country 
we have been identified with its interests as manufac¬ 
turers. As pioneers in the industry and during all 
these years it has ever been our special aim to keep 
pace with the various improvements that have been 
made from time to time in mining machinery and to 
give special attention to the arrangement of our shops 
and the perfection of our tools and patterns. 

Being in constant communication and direct con¬ 
nection with the best and most successful represen¬ 
tative men in the various branches of mining and 
ore treatment generally, throughout this and foreign 
countries, we are always in a position to learn and take 
advantage of such suggestions and changes from exist¬ 
ing methods as may be found to be of merit and real 
improvements in the mining and treatment of ores. 

Our large shops were overcrowded from the tre¬ 
mendously increased business which we had done in 
recent years, and we have built new shops in Chicago 
that have over three times the capacity of our former 
shops. We have also built new shops with large ca¬ 
pacity at Erith, Kent, England. 

We now have the largest shops in the world devoted 
exclusively to the manufacture of mining machinery. 
These shops are equipped with the best and most 
improved tools and a very large and varied assortment 
of patterns and plans. We are in a position to produce 


4 



first-class work to the advantage of our trade, and do 
it more promptly than ever before. 

Our facilities for the manufacture of Sectional 
Machinery adapted for transportation on pack animals 
in mountain districts are unexceled. We have made 
this a special feature, and have not only had a great 
deal of experience in the manufacture of such ma¬ 
chinery, but have also a very full and complete line of 
improved patterns. 

Our patrons may rest assured that we will not allow 
the reputation we have acquired as manufacturers of 
mining machinery to slip from us by failure to do good 
work or to keep up with this age of progress. They 
may rely upon us in obtaining the most practical out¬ 
fits, and not mere experimental machinery when de¬ 
siring to purchase standard and successful mining and 
ore reducing appliances. 

Mining plants, reduction and smelting works, etc., 
for which we have furnished all the machinery, can be 
seen in operation in every state and territory in this 
country where mining is followed. Besides this we 
have many plants in operation in Alaska, Canada, 
Mexico, Central and South America, China, Japan, 
Australia, Norway, Hungary, Spain, Portugal, Russia, 
South Africa, India, Italy and the Philippine Islands. 

Attention is called to the list of our other publica¬ 
tions on the inside back cover of this catalogue. 

These catalogues are sent post free to parties having 
a practical interest in the reduction and treatment of ores. 

We make all machinery required for the mining 
and metallurgical treatment of gold, silver, lead and 
copper ores, and parties contemplating the purchase of 
such machinery will find it to their advantage to write 
to us for estimates and specifications. 

FRASER & CHALMERS. 

Chicago, Iix., June, 1899. 

5 


FRASER & CHALMERS 


SAMPLING 


The value of a mine is determined from the analy¬ 
ses and assays of average samples of the ore. Ores 
are bought and sold from samples. Ores are combined 
with fluxes and smelted, the analyses of samples fur¬ 
nishing the metallurgist with data from which to cal¬ 
culate proper blast furnace charges. Ores can be 
sampled by hand or by machines, the former being the 
old-fashioned and expensive method, the latter, the 
modern method employed in sampling works. 

Every smelting plant should be equipped with 
machinery for sampling. 

We give descriptions, with illustrations, of some of 
the best machines used for automatic sampling. 


FRASER & CHALMERS MANUFACTURE 
CRUSHERS AND PULVERIZERS OF SUPERIOR 
MERIT & 


6 


FRASER & CHALMERS 


Plate 502. 



THE PIPE ORE SAMPLER 


This apparatus consists of a vertical pipe some 8 in. in 
diameter, provided with diaphragms near the top and sur¬ 
mounted by a funnel-shaped hopper; the sampler is usually 
placed in a bin. Plate 502 represents such a sampler. 


7 











































































FRASER & CHALMERS 


The finely crushed ore is fed into the hopper and passes 
over a dividing diaphragm which cuts it into two equal parts, 
one half being discharged into the ore bin, while the balance 
descends in the pipe and is thoroughly mixed by passing into 
a funnel, below which, it encounters a second diaphragm, 
which cuts it into equal parts, one half being discharged into 
the bin while the other half is mixed by passing through a 
funnel, cut into halves, etc. The plate shows how the ore 
and sample are collected and removed. 

This apparatus, while lacking the fine accuracy and great 
capacity of the Bridgman machines, will be found to serve a 
useful purpose where a less expensive plant is required and 
where power is not convenient. 


Plate 869. 



COLLOM’S SAMPLING MACHINE 

This machine (Plate 869) is used for taking, automatically, 
an average sample of ore below crusher or rolls as a check on 
the work of a mill. 

The arm with inclined channel revolves slowly, cutting 
an equal sample at regular intervals from the stream of ore 
falling from the rollers, all the samples being mixed and 
quartered down at the end of the day or run. 


8 











































































Plate 503. 


FRASER & CHALMERS 



McDERMOTT’S AUTOMATIC SAMPLER 

Plate 503 shows the McDermott Automatic Sampler, the 
construction and operation of which will be clearly under¬ 
stood from the following description : 

The worm wheel D revolves constantly, and pin G com¬ 
ing in contact with lever A , moves spout C into the stream 
of ore or pulp, causing a small portion of the current to be 
directed for an instant into the sample box H; the pin G ) 
having then passed the lever, it returns to original position by 
spring F. 

1. This arrangement of long-armed lever A with spring 
return enables the use of a slow revolving wheel, so as 
not to take samples too frequently, nor too large; so that the 
machine can run all day and not take too bulky a sample for 
convenient handling. The dividing launder splits up the 
stream of pulp in a large mill for the same purpose, viz., to 
keep sample small by passing sample spout C through only a 
part of the stream. 

2. The machine can be adapted to existing mills where 
“fall” is limited, either by making a few inches drop at 
some point in the main launder carrying pulp or tailings, or, 


9 




















































FRASER & CHALMERS. 


if this is not practicable, by using a long dividing launder, 
BB , which, being narrow and of metal, will clear itself with 
less fall than the main wooden launder. 

3. The frequency of the samples can be indefinitely in¬ 
creased by adding pins to the gear wheel D , or increasing 
speed of worm shaft E. 

4. The size of each sample taken can be varied by the 
widths of dividing launders and of sampling spout C; these 
being of thin sheet iron, can be bent by hand to desired width. 

5. Machines can be driven by i-inch rubber belt from any 
convenient line of shafting without any pulley on latter, 
simply letting shaft itself act as pulley and so giving slow 
motion to worm shaft. 

6. The dividing launder is not necessary where very small 
streams of pulp have to be sampled. 

7. The machine does more regular and more accurate 
work than the usual plan of sampling by hand. It has been 
tested for over a year in New York on all kinds of gold and 
silver ores—sampling pulp of a stamp battery, tailings of a 
concentrator, and discharge of a settler after pan amalgama¬ 
tion. This last is the most severe test a sampler can be put 
to, because settler discharge is extremely irregular. Its ac¬ 
curate work on the settler discharge has been proved in a 
great number of tests by check assays made on pan sample 
taken before discharge into settler. 

8. Every mill should have one to sample the pulp and 
one to sample the tailings. Great losses may be saved by 
systematic and accurate sampling in a mill. Millmen can 
not be trusted to take regular samples, and in some mills 
such great variations in daily assays occur that any estimate 
of actual work being done is little more than a guess. 

9. Machine being light and self contained can be bolted 
to the side of any main launder, or bolted on to any piece of 
timber supporting the launder. 


10 


FRASER & CHALMERS 



THE BRIDGMAN ORE SAMPLING MACHINE 


Plate 234. 












































































































FRASER & CHARMERS 


Sampling, to be of value, must be accurate and indepen¬ 
dent of personal influence. By using an automatic sampling 
machine not only are the inaccuracies of hand labor avoided, 
but the cost of the operation is greatly reduced. 

Mr. H. L. Bridgman, M. E., has given to the mining 
world a most valuable machine which accomplishes all to be 
desired in an ideal automatic sampler. This statement is 
substantiated by abundant evidence from our patrons. The 
machine is constructed on the best scientific principles. It 
is the result of years of practical experience. 

Plate 234 shows the general appearance of the machine. 

It affords a method of sampling far in advance of any 
other, either by hand or by machine. Following are the 
principal advantages : 

1. It gives entirely independent double (duplicate) sam¬ 
ples on every lot of material, affording the best possible con¬ 
trol of results, and rendering “ salting ” impossible. 

2. It gives three or more cuts (quarterings) on each 
sample during a single passage of the material, thus yielding 
practically finished samples in one operation. 

3. It is the only machine that does these things, and 
both points are broadly covered by United States and foreign 
patents. 

4. It samples according to the only correct principle of 
taking the entire stream of material for certain predetermined 
periods of time, and does not attempt to take a portion of 
the stream for the whole time. 

5. It is entirely self contained and very compact. 

6. It takes its feed directly from the crusher, and gives 
good results, equal to the best hand sampling, under any 
ordinary working conditions. 

7. It requires not more than the power of one man to 
run it. 


12 


FRASER & CHALMERS 


8. It requires no lubrication, except at long intervals. 

9. It requires a minimum of repairs. 

10. It will sample any material that can be crushed, even 
up to 10 per cent, or more of moisture. 

11. It can be thoroughly cleaned by one man in fifteen 
minutes. 

12. It may be fully inspected during operation without 
the necessity for the near approach of any person. This will 
avoid suspicion of unfairness by enabling those who desire to 
watch the work. 

13. It requires not over one-tenth the space that hand 
sampling does. 

14. It reduces the cost of sampling to one-tenth that of 
hand-work, and does not, like present methods, require the 
use of the best judgment and the greatest vigilance, but 
rather a mere faithful performance of routine. 

15. It is free from all personal influence and entirely im¬ 
partial, thus avoiding disputes. 

16. It gives final samples so quickly that all lots may 
be sampled and disposed of as soon as received. This quick¬ 
ness, furthermore, makes it possible to use the machine sam¬ 
ples for moisture determinations as well as for the metals, 
thus saving work and getting fairer assays. 

17. It is adjustable and gives larger or smaller final 
samples, as may be required by the different grades and kinds 
of material. 

The following sizes of machines and apparatus have been 
designated to meet the various requirements : 

Machine “A” 

Gives double samples and three cuts (quarterings) on each 
sample. It is intended for original samples of any size, and 
gives final samples of about 1 or 2 per cent, of the original 


13 


FRASER & CHALMERS 


weights. It requires a floor space 3 by 4 ft., and has a height 
over all of 7 ft. 6 in. Its average capacity is about 20 tons 
an hour. 

Machine “B” 

Gives a single sample and three cuts. It is intended for 
smaller original samples than the “A” machine, and for 
work requiring only a single sample, as, for instance, iron 
ores, the various furnace supplies and products, etc. It is 
especially designed for the cutting down of the crushed final 
samples from the “A” machine. It occupies a floor space 
about 18 in. square, and is about 36 in. high. Its average 
capacity is 2 to 4 tons an hour. 

Machine “D” 

Laboratory sampler for small work. 

Mixer and Divider 

For the final preparation and distribution of the assay 
samples. 

A full description of the Bridgman Ore Sampling 
Machines, illustrated with cuts, as well as valuable informa¬ 
tion relating to sampling, is contained in our Pamphlet No. 
32A, copies of which will be sent on application. 



14 


FRASER & CHARMERS 

Plate 56. 



Plate 56 illustrates our Sample Grinder. This is a very 
useful machine in any works, and is especially necessary in 
a custom mill. The coarsely crushed sample for assay is 
rapidly ground to fine powder, and is caught below in pans 
from two spouts; the distributing case and spouts are dust- 
housed; cleanliness is thereby assured and the escape of dust 
prevented. The degree of fineness can be regulated by the 
hand-wheel shown in the cut. 


The Sample Grinder is sold complete and ready for belt. 


Speed. 

Diameter of 
Pulleys, 

Tight and Loose. 

Face of 
Pulleys. 

Weight, 

Not Boxed. 

Weight, 

Boxed. 

Horse Power. 

150 

16 in. 

4 L* in - 

775 lbs. 

900 lbs. 

3 


15 





























































































































































Plate 245 


FRASER & CHALMERS 




C/) 

C 



16 









































































































































































Plate 246 


FRASER & CHALMERS 


R. R. Track 



17 


Ground Plan 

Improved Sampling Works 

(Arranged for level ground site) 

Using Bridgman’s Sampling Machines 

Capacity, 10 Tons an Hour 





























































































































































































































































































Plate 247 


FRASER & CHALMERS 



Capacity, 10 Tons per Hour 



















































































































































































































FRASER & CHALMERS 


Plate 248 



Improved Sampling Works 

(Arranged for Hillside) 

Using Bridgman’s Sampling Machines 

Capacity, 10 Tons per Hour 


19 














































































































































































































































































FRASER & CHALMERS 


SAMPLING WORKS 

USING BRIDGMAN’S SAMPLING MACHINES 
Capacity, ioTons an Hour 


The following explanation applies to the plans both for 
LEVEL ground (Plates 245 and 246) and for hillside 
(Plates 247 and 248), the general arrangement being the 
same for both: 

These Sampling Works are designed to handle both oxide 
and sulphide ores at a rate of about 10 tons per hour, of 
material actually sampled, provided the ores be not excess¬ 
ively hard to crush. For sulphides it is generally desirable 
to sample the entire lot, and this course is also strongly 
advised for oxides of high value and of which it is desired to 
obtain very accurate samples. This is rendered unobjection¬ 
able because of the fact that the arrangement followed herein 
permits of the sampling of an entire lot in less time and at 
less cost than would be required for the sampling of one-fifth 
of the lot by hand, with the further advantage of greatly in¬ 
creased accuracy in the finished samples. In case, however, 
it is desired to preserve the oxides in a coarse lump form 
rather than to obtain greater accuracy of sample, the main 
bulk of the lot is thrown into bin “B”, while such fractional 
part of said lot as may have been predetermined is thrown 
into bin “A”, as the “first rough sample”, which then is 
passed to the sampling, the main bulk going by cars to the 
general storage bins or to whatever point desired. It is ad¬ 
visable to limit maximum size of ore passing to Automatic 
Sampler to not more than two inches, ring gauge. Whichever 


20 


FRASER & CHALMERS 


course be adopted, either the main bulk or the “ first rough 
sample’'' would be subjected to the following treatment 
which is that for Oxide Ores : The ore is taken from bin 
by dump car to crusher, into which it is fed by hand as reg¬ 
ularly as possible, avoiding rolls “ A ” (supposing crusher to 
be set for two inches or less), and passing to elevator “A”. 
Thence it rises to equalizing bin (by means of which con¬ 
veyor trough “T” is always to be kept full), and is fed 
regularly by screw “S” to Bridgman’s Automatic Sampler 
“ A ” which cuts out duplicate “first finished samples ” of 
proper and variable size and discards the bulk which passes 
to elevator u B This “ discard ” then rises and is deflected 
to bin “C” and goes thence by dump car to general storage 
bins. The duplicate “ first finished samples ” are then hoisted 
from below and treated separately, each being crushed very 
finely by small rolls “ C ” and then cut into “ second finished 
sample” and u discard’’ by Bridgman’s Automatic Sampler 
“ B ”, the former going to the F. & C. Sample Grinder and 
thence to the Assay Office, and the latter being delivered to 
bin “C” by means of elevator “B” as in the case of the 
main bulk. 

Sulphide Ores : These as a rule and for obvious rea¬ 
sons, require to be crushed very finely both for sampling and 
for subsequent treatment, although it is permissible to crush 
somewhat coarser for the former than for the latter. In 
order to avoid all segregation by sizing until after the sam¬ 
pling has been finished the following order is to be observed : 
The entire lot of ore is taken from bin “ B ” by car to 
crusher, from which it passes to rolls “ A ” (set for or ^ 
inch), thence to elevator “A”, equalizing bin, and Auto¬ 
matic Sampler which cuts out duplicate “first finished sam¬ 
ples”, the “discard” going by means of elevator “B” to 


21 


FRASER & CHALMERS 


revolving screen mesli) over bin “D” into which the 
undersize falls and is taken by cars to general storage bins. 
The oversize falls to rolls “B” (set fine), and thence to ele¬ 
vator “ B ”, by which it is again raised to screen for sizing. 
The “first finished samples” follow the same course as that 
taken by those from the oxides. For public sampling, the 
rolls u B ”, bin “ D ”, screens, etc., may be dispensed with, 
since the second fine crushing is not demanded. As it stands, 
the plant is arranged for smelting works. 



22 


FRASER & CHALMERS 


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Roasting 


Methods 

Roasting Furnaces 



Reverberatories 
The Brown Furnaces 
Bruckner Roasters 
White=Howell Roasters 
Stetefeldt Roasters 
Muffle Furnaces 


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23 


FRASER & CHALMERS 


ROASTING 

Roasting is oxidation under the influence of heat in the 
presence of air, its object being to effect such chemical changes 
as will render the material suitable for smelting, amalgama¬ 
tion or lixiviation. By this operation sulphur and arsenic 
are more or less eliminated, as well as some antimony and 
zinc. 

Ores in the lump form which contain sufficient sulphur 
may be roasted in heaps, stalls, or kilns, or, if crushed, in 
roasting furnaces. Lump ore containing as little as 15 per 
cent, of sulphur can be roasted in heaps without the ad¬ 
mixture of considerable fuel through the rock. 

Roasting operations may be classed under one of three 
heads: oxidizing, chloridizing and sulphate roasting. 

OXIDIZING ROASTING 

Sulphide ores and mattes can be subjected to the opera¬ 
tion of oxidizing roasting in either a lump or a pulverized 
condition. Those intended to be smelted are often roasted 
in the lump form in either heaps, stalls, or kilns. Roasting 
in this manner is not as perfect as when the ore is pulverized; 
but the lump form is preserved and the disadvantage of 
smelting fine material in the blast furnace avoided. 

To avoid the objection to charging fine roasted ore into 
the blast furnace, sulphides are often first roasted and then 
slagged, both operations being performed in the same rever¬ 
beratory furnace; in this case, the ore must be of such com¬ 
position that it will slag under a higher heat than is required 
for roasting, or other ores must be mixed with it to produce 
a slagging mixture. 

Again, to avoid charging fine roasted ore into the blast 
furnace, certain ores, such as galena, are raised to a high 
heat at the last stage of the roasting whereby they become 


FRASER & CHALMERS 


sticky and agglutinate, and when cold the mass can be broken 
up into lumps. 

In smelting plants, flue-dust is a difficult and expensive 
by-product to handle, and is often charged into the slagging 
pit of a roasting fusion reverberatory furnace and incorpo¬ 
rated with the slagged ore, which avoids the necessity of 
bricking it. 

Oxidizing roasting prepares ores and mattes for many 
subsequent metallurgical operations, some of the principal 
ones being the following: 

For Chlorination 

Gold often occurs so associated with other substances 
(usually sulphur, arsenic, antimony, etc.) that, to extract it, 
the ore must first be roasted. 

The roasting of auriferous iron sulphurets is a simple 
operation. The material may be either ore (in which 
case it must be previously crushed) or sulphurets obtained 
by concentrating the pulp from stamp mills. Upon the 
thoroughness of the roasting, or, in other words, upon the 
perfectness with which the sulphur is eliminated, depends 
more or less the complete extraction of the gold by chlorine. 

For roasting sulphurets for chlorination, reverberatory 
furnaces, either stirred by hand or mechanically (the Brown 
roaster), are almost exclusively used. 

For Cyanide Process 

Some ores which in their raw state do not yield a high 
percentage of extraction when leached with cyanide solution, 
do so after having been roasted. 

For Smelting 

By roasting ores previous to smelting, much sulphur and 
arsenic will be driven off, which will reduce the amount of 


25 


FRASER & CHALMERS 




iron otherwise necessary to be added in the blast furnace to 
decompose the sulphides and arsenides, and with it the 
amount of matte and speise, thus increasing the capacity of 
the furnace. 

As a rule, ores containing as much as 15 per cent, of 
sulphur should be roasted previous to smelting; the richness 
of the ore in silver may, however, modify this rule on account 
of the loss of silver in roasting. 

Silver ores containing as much as 100 ounces of silver 
per ton are seldom roasted. 

When there is much blende in the ore it should be roasted, 
as in the form of oxide it more readily passes into the slag. 

Copper sulphide ores produce a higher grade matte if 
roasted previous to smelting them. Copper mattes are often 
roasted and then smelted with silicious ores in order to slag 
off the oxide of iron; this concentrates the matte and brings 
it up to a percentage of copper which permits of it being 
either shipped or bessemerized. 



26 



FRASER & CHALMERS 


\ 


CHLORIDIZING ROASTING 

Chloridizing roasting consists in roasting the material, 
(whether it be an ore or a matte) with common salt, the 
metal which it is desired to extract being obtained in the 
roasted product in the form of chloride ; in the case of silver, 
the silver chloride can then be extracted by amalgamation 
or by lixiviation with sodium hyposulphite. 

Chloridization in the roasting furnace is effected by the 
action of the sulphuric acid of the sulphates formed by the 
oxidization of the sulphides on the salt which liberates 
chlorine, from which it will be seen that for successful chlori¬ 
dizing roasting there must be a certain percentage of sul- 
phurets present in the raw ore. 

Chloridizing roasting is confined principally to silver 
ores, and for this operation the ores must necessarily be pul¬ 
verized. 


SULPHATE ROASTING 

Ores and mattes are sometimes roasted without salt, the 
silver contents being converted into silver sulphate and then 
leached with water (Zievogel process). There are also pro¬ 
cesses for extracting copper in a similar manner. 


FRASER & CHALMERS ARE MANUFACTURERS 
OF COMPLETE MINING, MILLING AND SMELT¬ 
ING EQUIPMENTS. & 


27 


FRASER & CHALMERS 


Plate 81S 



The Guyer Desulphurizing Kiln 


28 










FRASER & CHALMERS 


THE GUYER DESULPHURIZING KILN 

In small plants where development of the property does 
not warrant expensive crushing and roasting machinery, and 
where the ores are suitable for heap or stall roasting, “The 
Guyer Desulphurizing Kiln” (Plate 818) can be used to 
advantage for the purpose of partial desulphurization. 

Capt. Henry Guyer, of Casapalca, Peru, has had several 
of these kilns in operation for some time with excellent 
results. In a letter under date of November 15, 1898, he 
writes us that he ran one of these kilns at the rate of seven 
tons per day at a cost of 34 soles (33 cents silver) per ton, and 
that in one week in October of the same year he ran at the 
rate of thirteen tons per day at a cost of 18 soles (18 cents 
silver) per ton. The original ore contained 27 per cent, of 
sulphur, and was reduced by roasting to 8.8 per cent. 

Ores to be roasted in this furnace must be coarse, from 
the size of corn to about the size of an egg, and should not 
contain less than 20 per cent, sulphur. The only fuel used is 
a few shovels daily of charcoal dust, shavings, or any rubbish 
that will burn. 

We make these kilns of as small a capacity as two tons 
per day. 

The furnace is very simple, consisting of a four-sided 
grizzley, constructed principally of grate bars fastened to a 
rectangle made of rails, which is supported on pipe columns ; 
this is surmounted by a sheet-iron hood having a hole in the 
top for charging and one on the side for connection with a flue. 


29 


Plate 776 


FRASER & CHALMERS 



30 


Reverberatory Roasting Furnace 































































































































































































































































FRASER & CHALMERS 


ROASTING FURNACES 

Roasting furnaces may be classified under one of the fol¬ 
lowing types: the hand-stirred reverberatory ; the reverber¬ 
atory with continuous discharge (Brown ); the revolving cyl¬ 
inder with intermittent discharge (Bruckner); the revolving 
cyclinder having continuous discharge (Wliite-Howell); shaft 
furnaces (Stetefeldt); muffle furnaces (Brown). 

With the above mentioned furnaces, wood, coal, gas, or 
oil can be used as a fuel, and all are intended for roasting 
crushed ore. 


THE REVERBERATORY FURNACE 

The ordinary reverberatory roasting furnace consists of a 
continuous hearth covered over with a low arch and having 
a fire-box at one end and a flue at the other. 

The furnace can often be economically built of stone up to 
the hearth level, the rest of the structure being constructed 
of brick and the entire mass bound together with u T ” rails 
and wrought iron tie rods. 

The hearth should be of sufficient area to suit the char¬ 
acter of the ore and the tonnage required. We make them 
all the way from 7 x 10 ft. to 17 x 72 ft. 

Plate 776 shows the general construction of a reverberatory 
roasting furnace in plan and elevation. 

Ore is charged into the furnace through a hopper and 
gradually advanced from the cool end to the hot end by 
means of iron paddles and rabbles, and when roasted it is 
raked out into a car or wheelbarrow, or into a pit. 


31 


FRASER & CHALMERS 


Reverberatory furnaces are sometimes built with the 
hearth in steps, that - is, beginning with the fire-box end, 
every io or 15 feet lengthwise of the hearth being raised a 
few inches higher than the preceding section. This con¬ 
struction permits of keeping the charges in the furnace 
entirely separate from each other; it is also claimed that, 
by dropping the ore through the air from one hearth to the 
next, roasting is facilitated. 

Reverberatory furnaces are sometimes built with half the 
length of the hearth placed over the other half, thus forming 
a two-tier furnace; they have also been built in three tiers. 
Some mechanically stirred reverberatories, especially those 
used for roasting zinc where the fumes are recovered and 
converted into suphuric acid, are made even six tiers high. 

Again, two reverberatories may be placed side by side, 
the central wall being common to both furnaces; in this case 
the furnaces can be worked from one side only. 

The advantage of the hand-stirred reverberatory is that 
its first cost is small; the disadvantages are, that roasting is 
expensive and the results obtained are irregular. 

THE SLAGGING=REVERBERATORY 

The slagging-reverberatory, or roasting-fusion furnace, 
Plate 57, is largely used by smelting companies. It consists 
of a long, brick hearth, sometimes built in “steps” covered 
over with a low arch, and terminating next to the fire-box in 
a fusion-box, or slagging pit. As a high heat is carried in 
the slagging pit, the fire-bridge is usually provided with a 
water-jacket or coil of water pipes. Ore is charged into the 
upper end through a hopper and gradually worked forward, 
being roasted during its passage, as in the ordinary reverber¬ 
atory roaster, until it reaches the fusion-box, where, being 
subjected to a high heat, it is fused or slagged down; from 
the fusion-box it is drawn out at intervals into slag pots, 
cooled, broken up, and charged into a blast furnace. 


32 


Plate 57 



33 

































































































































































































FRASER & CHAEMERS 


Plate 57 illustrates a furnace of this type which has given 
great satisfaction at the works of the Omaha & Grant Smelt- 
ing and Refining Co., the Hanauer Smelting Co.’s works, 
and elsewhere. 

These furnaces are built in various sizes ; the one we have 
represented is 72 ft. long by 17 feet wide. 

The capacity of a reverberatory roasting furnace depends 
chiefly upon the percentage of sulphur the ore contains and 
the delicacy of the roasting required. Heavy galena ores 
and pyrites roasted for smelting require from 85 to 92 sq. ft. 
of hearth area per ton of ore roasted per 24 hours ; fine 
pyritic concentrates roasted for chlorination require about 
169 sq. ft.; in the former case the roasting is imperfect, there 
being left in the roasted ore from 3 to 5 per cent, of sulphur, 
while in the latter less than one-half of 1 per cent, is per¬ 
mitted to remain. 

Roasting by hand is hard work and requires conscien¬ 
tious labor, results are often very irregular and unsatis¬ 
factory, and the cost of roasting is much more than in 
mechanical roasters. 

Experience having proved that the reverberatory is the 
best type of roaster for nearly all classes of ore, many have 
studied to invent mechanical means to take the place of 
hand labor. Of the many inventions in this direction, “The 
Brown Roaster” is by far the best, its uniform results, 
arrangements for admission of air in the proper places, proper 
distribution of heat, etc., permitting of a large reduction in 
hearth area over that of the common reverberatory, which 
means that, for a certain duty, a smaller furnace, less ground 
room and building, and less labor will be required. 


MORE THAN TEN THOUSAND STAMPS HAVE 
BEEN SOLD BY FRASER & CHALMERS. ^ ^ ^ 


34 


FRASER & CHALMERS 


Plate 781 








The Brown Straight Roasting Furnace 


35 



















































































































































































































































































































FRASER & CHALMERS 


THE BROWN ROASTING FURNACE 

In its most improved form the Brown Roasting Enrnace 
is a single hearth reverberatory with an interior slotted wall 
on each side of the hearth, covered with a low arch (see Plate 
7 8i > Fi g- !)• 

In the conduits formed by the slotted walls and the exte¬ 
rior walls of the furnace, are placed rails upon which run 
trucks supporting a stirrer arm, projecting through the slots. 
Fastened to that portion of the arm which extends over the 
hearth are stirrer shoes, resembling miniature plow-shares, 
which dip down into the ore, lying in a thin layer on the 
hearth. 

The stirrer carriages (there are never less than two) are 
moved through the hearth in the direction of the fire-box by 
two endless steel link chains which pass over sprocket 
wheels located at both ends of the furnace outside of the 
roasting hearth (see Fig. 2). After passing through the 
hearth each carriage returns over the top of the arch in the 
direction of the flue on tracks similar to those placed in the 
conduits (see Fig. 1), and having reached the end of the arch 
it passes downwards into the hearth again. There are sheet 
iron flap doors, hinged at the top, placed at both ends of the 
roasting hearth to keep out the cold air; these remain 
closed except when lifted by a stirrer carriage passing in 
and out. 

By this construction the operating mechanism is protected 
from the furnace heat and fumes, and the carriages, by pass¬ 
ing over the top of the furnace into the open air, have time to 
cool off. With this provision for cooling, the stirrers do not 
become over-heated. 


36 


FRASER & CHALMERS 


The slotted walls are formed by fire-clay tiling which 
project upwards from the hearth and by firebrick which 
project downwards from the arch. 

The skew-backs of the arch are steel channels supported 
on short columns, the spaces between the columns being 3 ft. 
6 in. long by 12 in. high, these openings extending the entire 
length of the hearth, forming a continuous slot on both sides; 
they are closed by sheet-iron doors lined with asbestos. This 
construction permits of ready access to the hearth at any 
point for repairs, etc., without having to tear down the brick 
construction to get to the interior of the furnace. 

From the ground to the hearth the furnace may be con¬ 
veniently built of uncut stone, and the rest of the furnace 
constructed of brick, the structure being bound together by 
steel I beams. 

By the stirrers passing over the top of the furnace instead 
of underneath, as is the case with several other mechanical 
furnaces, the furnace can be built lower and therefore more 
convenient, and the absence of air space beneath the hearth 
means reduced loss of heat by radiation and hence economy 
in fuel ; less iron work, consequently cheaper construction. 

Fire-boxes, in number and position to suit the length of 
the furnace and the character of the ore, are provided; they 
are arranged in pairs opposite each other in the usual con¬ 
struction (see Fig. 3). 

When subsequent operations, such as chlorination, leach¬ 
ing, etc., render it necessary to cool the roasted ore rapidly, 
the top of the furnace is converted into a cooling floor by 
covering it with thin steel plates having upturned edges, the 
construction being that of a shallow tray the length of the 
arch and the width of the roasting hearth; special double 
arm stirrers are provided with which to raise the ore from 
the roasting hearth to the cooling pan along which it is 


37 


SECTIONAL PLAN OF EIRE BOX AND flue inlet. 


FRASER & CHALMERS 



38 


The Brown “Horseshoe” Roasting Furnace 









































































FRASER & CHALMERS 


gradually advanced, in the same manner as in the hearth, to the 
cool end of the furnace, where it may be carried away by a 
conveyor or other device. The ore, red hot when leaving 
the roasting hearth, is in this manner rapidly cooled and can 
be directly charged into barrels, tanks, etc. 

With this furnace we provide an automatic ore-feeder and 
all driving mechanism complete, also a small slide-valve 
engine, enabling the furnace to be run independently of the 
other mill machinery. 

The Brown Roaster is also made round in shape, as shown 
in Plate 563, oval as in Plate 564, and in fact of any desired 
shape to suit local conditions. 

When made other than straight, the stirrer carriages are 
drawn by an endless steel wire rope which runs in the inner 
conduit and is supported on small horizontal grooved wheels 
placed sufficiently near each other to cause the rope to conform 
to the curve of the furnace; the rope is driven and kept taut 
by passing it around a system of wheels driven by a small 
slide-valve engine provided for that purpose. 

The rope is connected with the carriages by means of a 
small grip similar to that used on cable cars and is made to 
open and shut automatically, the construction being such 
that as soon as a carriage emerges from the hearth into the 
open air it is unclutched and remains there cooling off until 
the carriage behind it emerges and strikes it, pushing it for¬ 
ward a short distance to a point where it becomes again 
clutched to the rope and travels forward while the second 
carriage becomes unclutched and remains stationary. These 
operations are performed automatically. 

As can be readily seen, in these designs of the furnace, 
the carriages travel constantly on the same horizontal plane. 
Should it be desired to have a cooling-hearth, then enough of 
the hearth must be left uncovered to serve this purpose. 


39 


ZJ.EVATOA 


FRASER & CHALMERS 



40 


The Brown “Oval” Roasting Furnace with Cooling Hearth 














































































































































































































































FRASER & CHALMERS 


SIZES OF BROWN ROASTERS 

We have found from experience that in the straight fur¬ 
nace the best width for the actual roasting hearth is io ft., 
and for the furnaces which have a curved hearth, 8 ft. The 
straight furnace may vary from 60 ft. to 180 ft. in length, 
and the diameter of the round ones may be from 50 ft. up¬ 
wards. In localities where economy in floor space need not be 
considered, the round or the oval type may be used, being 
simpler in construction and costing less per square foot of 
hearth area than the straight furnace. 

Where space is limited the straight furnace should be 
used. 

We recently sold two Brown Roasters of the round or 
“horseshoe” type, each 119 ft. in diameter, and each having 
2,422 sq. ft. of effective roasting hearth. Plate 830 is a 
photographic reproduction showing these furnaces in process 
of construction. 

No regular building will be necessary; over the arch will 
be a roof (preferably of corrugated iron), the central space 
being left open. 


CAPACITY OF BROWN ROASTERS 

Silicious ores containing from x / 2 to 3^ per cent, of sulphur 
will require from 13 to 15 sq. ft. of hearth per ton; mattes 
which usually contain from 18 to 20 per cent, sulphur, when 
it is required to bring the sulphur down to about 4 percent., 
need about 45 sq. ft.; sulphide ores roasted for smelting pur¬ 
poses require from 33 to 35 sq, ft. For roasting iron sulphide 
concentrates which carry from 35 to 45 per cent, down to T 5 ¥ 
per cent, sulphur, from 55 to 60 sq. ft. will be required. 

From these data it will be easy to select a Brown Roaster 
of the proper size for any required duty. 


41 


Plate 830 


FRASER & CHALMERS 




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42 

















FRASER & CHALMERS 


FUEL REQUIRED FOR BROWN ROASTERS 

From ioo to 135 lbs. of coal are required per ton of sili- 
cious ore and about half that amount for concentrates roasted 
down to about 4 per cent, of sulphur. 

When it is necessary to roast sulphide ores and mattes to 
below 1 per cent, of sulphur a higher heat and more fuel will 
be required, the fuel expense increasing in proportion to the 
perfectness of the roasting. 


ADAPTABILITY OF THE BROWN ROASTER 

All ores and mattes in a pulverized condition which have 
to be roasted for subsequent metallurgical operations can be 
satisfactorily roasted in the Brown Roaster. 


POINTS OF SUPERIORITY OF THE BROWN ROASTER 

Simplicity of construction, large capacity, uniformity of 
results, economy in fuel and labor, cheapness of first cost 
(efficiency considered), small flue-dust loss, durability, readi¬ 
ness and cheapness with which repairs can be made, and 
portability, a most desirable feature when transportation is 
necessary to a distant locality difficult of access. 


STAMP MILLS, ROCK CRUSHERS, HUNTING- 
TON MILLS, J* RIEDLER PUMPS, & HOISTING 
ENGINES. WRITE TO FRASER & CHALMERS 
FOR CATALOGUES AND ESTIMATES & # 


43 


FRASER & CHALMERS 


THE BRUCKNER ROASTER 

This well and favorably known type of roaster consists of 
a horizontal cylinder of boiler iron, lined preferably witli 
fire-brick, the cylinder resting on friction rollers and revolv¬ 
ing between a fire-box and a flue. The flame from the fire- 
box passes directly through the cylinder, and thence, mixed 
with the gases from the ore, into a dust chamber. The cyl¬ 
inder is provided with manholes for receiving and discharg¬ 
ing ore. 

Plates 194 and 188 show the construction of the Bruckner 
Roaster. 

The cylinders are made to revolve slowly, the smaller 
ones by applying power to a shaft carrying the friction 
rollers, the large ones by a pinion which engages a spur-gear 
surrounding the cylinder. The fire-box is made either 
movable or stationary. In the former case it is constructed 
in the form of a car running on a track, usually (but not 
invariably) placed at right angles to the axis of the cylinder, 
and having a short flue on one side that comes exactly oppo¬ 
site the throat of the furnace. In this way the fire-box can 
be run in front of a cylinder containing a fresh charge and 
fired until the sulphur is thoroughly ignited, and then run 
opposite another cylinder, leaving the first to complete the 
combustion of the sulphur with free access of air undisturbed 
by reducing gases which would necessarily pass through the 
fire-box. After the combustion of the sulphur, for its perfect 
elimination extraneous heat will be required, and the fire-box 
can again be placed in front of the throat of the cylinder (see 
Plate 194). 

For ores low in sulphur, requiring the application of 
extraneous heat during the entire operation, a fixed fire-box 
may be used (see Plate 188). 


44 


Plate 194 


FRASER & CHALMERS 



Bruckner Roasting Furnace 

8 )/ z x 18 y z ft., with movable firebox. 


































































































































































































































































































































































































































































































































































Bruckner Roasting Furnace 


FRASER & CHALMERS 



46 






































































































































































































































































































































































FRASER & CHARMERS 


Ore is roasted in this furnace in charges of several tons, 
and the charge be retained in the cylinder as long as re¬ 
quired, the time depending upon the character of the ore, 
thoroughness of the roasting required, etc., varying from 
four to twenty-four hours. 

Bruckner Roasters have been in use many years and are 
very popular with smelting companies ; to the Anaconda 
Copper Mining Co. alone, we have sold 252 Bruckners, 8 */ 2 
ft. by 18 ^ ft. 

The principal advantages of this type of roaster are that 
the charge can be held in the furnace as long as may be re¬ 
quired, the heat can be nicely adjusted, and roasting can be 
economically performed. 

We make this roaster in several sizes, from 32 in. diam. 
by 60 in. long, for experimental purposes, up to those 8 */ 2 ft. 
diam. by 28 ft. long. 


APPROXIMATE CAPACITIES AND MATERIAL 
USED IN CONSTRUCTION 


Size of Furnace, 

Inches. 

Weight of 

Iron Work. 

Number 

Fire Brick. 

Number 
Common Brick. 

22 in. bv 60 in. 

2,600 lbs. 



6 ft. by 12 ft. 

17,800 “ 

I , 3 °° 

18,000 

7 ft. by 18 ft. 

30,000 “ 

E 7 00 

20,000 

8*4 ft. by 18 y 2 ft. . . 

52,000 “ 

2,800 

25,000 

8*4 ft. by 28 ft... . 

69,000 “ 

3 ) 3 °° 

27,000 


47 















FRASER & CHALMERS 














































































































































































































































































































































































































































































































































































































































































































FRASER & CHALMERS 


THE WHITE= HOWELL ROASTING FURNACE 

Plate 41 illustrates the well-known White-Howell Roast¬ 
ing Furnace. It consists of a long telescopic shaped iron 
cylinder, made in sections to facilitate transportation, slightly 
inclined, supported on friction rollers and revolved between 
a stationary fire-box and a flue. That portion of the cylinder 
nearer the fire has a larger external diameter than the 
part next to the flue, but it is lined with fire-brick to 
make its internal diameter the same as that of the smaller 
part, which although unlined, stands the heat very well. Pro¬ 
jecting fire-brick arranged spirally in the brick-lined portion 
assist in oxidation by raising and showering the ore through 
flame, which it will be understood passes directly through 
the cylinder, and for the same purpose the unlined part is 
provided with cast-iron shelves. 

The furnace is fed at the upper end with dry pulp by 
means of a suitable screw feeder, and the pulp makes its way 
automatically toward the lower end of the furnace where it 
passes out, dropping between the end of the cylinder and the 
fire-box into a vault. 

Sometimes an auxiliary fire-box is placed at the flue end 
of the roaster (see Plate 41) for roasting the flue-dust as it 
passes, suspended in the air, into the dust chamber. 

The White-Howell Roaster has given excellent satisfac¬ 
tion for many years, its principal use having been for chloridiz- 


49 


FRASER & CHALMERS 


ing silver ores for amalgamation, or leaching with sodium 
hyposulphite. 

For these roasters we furnish complete iron work, consist¬ 
ing of cast-iron cylinder (in sections with bolts), truck wheels, 
shafts, bearings, frames, guide stands and rollers, gears, 
pulleys, end plates, fire doors, discharge doors, grates, binders, 
tie rods, feed-hopper, flue doors, etc. 


SIZES, WEIGHTS AND CAPACITIES OF 
WH1TE=H0WELL ROASTERS 


Diameter. 

Length, 

Feet. 

Capacity 
in Tons. 

Weight of 
Iron Work, 
Lbs. 

Fire Brick 
Required. 

Common 

Brick 

Required. 

3 1 

in. by 41 in. 

23 

15-20 

25.500 

1,900 

22,000 

52 

in. by 62 in. 

27 

30-50 

43.500 

2,700 

28,000 


DREDGES AND OTHER EQUIPMENTS FOR 
PLACER MINING, ALSO PUMPS, COMPRESSORS, 
DRILLS AND HOISTING ENGINES FOR DEEP 
MINE WORK, 


50 

















FRASER & CHALMERS 



Plate 144 


, Avvv;A.|'A''xy/ 

: n \\ • r 


mmm 


W4m 


Stetefeldt Roasting Furnace 


51 











































































































































FRASER & CHALMERS 


THE 5TETEFELDT ROASTING FURNACE 

The Stetefeldt Roasting Furnace consists of a vertical 
brick shaft some 25 feet high, having a fire-box near the bot¬ 
tom and a flue-opening near the top ; by means of a screen 
feeder, worked automatically, pulverized ore is continually 
sifted into the shaft and, in falling through the heated air, 
which takes but a few seconds, it is roasted. 

There is also a fire-box placed at the bottom of the de¬ 
scending flue for roasting the flue-dust, which may amount 
to as much as 30 per cent, of the ore. 

We are prepared to furnish the iron work for this type of 
roaster in three sizes : 

No. 1. Capacity 10 to 20 tons per 24 hours. 

2. v “ 20 to 40 “ “ 24 “ 

3. “ 40 to 80 “ “ 24 “ 


FRASER & CHALMERS DESIGN AND MANU¬ 
FACTURE CONCENTRATION PLANTS, CHLO¬ 
RINATION WORKS, CYANIDE MILLS ^ jt jt 


52 


FRASER & CHALMERS 


nUFFLE FURNACES 

Muffle furnaces are closed reverberatories so constructed 
that the products of combustion from the fuel are not allowed 
to mix with the gases evolved from the ore. Such a furnace 
may consist of one long continuous muffle or several muffles 
arranged in tiers one above the other in one furnace 
construction. 

Muffle furnaces are chiefly used for roasting iron pyrites 
and zinc blende when it is desired to collect the sulphurous 
acid fumes, free from mixture with fuel gases and from excess 
of air, for the manufacture of sulphuric acid. 

Plate 779 shows a cross-section through a Brown Muffle 
Furnace which was recently shipped to a customer in Europe. 
The hearth is io x 150 ft., arranged to be heated by 
“producer” gas. The large spaces directly beneath the hearth 
are combustion chambers where the fuel gases are burnt. 
Double doors at either end of the hearth prevent excessive 
admission of air into the hearth when the stirrer carriages 
pass in and out, the distance between the doors being such 
that one is opened and shut before the other is opened ; in 
other respects the furnace is like the Brown Straight Roaster 
(Plate 781). 


53 


Plate 779 


FRASER & CHALMERS 



54 














































































































































FRASER & CHALMERS 


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55 





FRASER & CHALMERS 


SMELTING 


To melt or fuse ore for the purpose of separating the 
metal or its sulphur compound from its gangue is called 
smelting. It consists in subjecting ores mixed with suitable 
fluxes to the action of intense heat, whereby the materials 
become fluid, the gangue of the ore combining with the 
fluxes to form a usually worthless slag or scoria, while the 
valuable portions combine together to form an alloy or matte, 
the separation taking place while the materials are in the 
molten condition by difference in their specific gravity. 

Smelting is performed either in a blast furnace where the 
fuel (coke or charcoal) is mixed with the ore and fluxes, or in 
a reverberatory where it is burnt in a separate fire-box. 

Smelting as we will consider it, relates to the treatment of 
gold, silver, copper and lead ores in blast furnaces, and it is 
covered by the following modifications: 

1. Smelting to silver-lead bullion. 

2. Smelting to copper - matte in the case of copper 
sulphide, or to black copper should the ores be oxides and 
carbonates. 

3. Compromise pyritic smelting. 

4. Iron-matte smelting. 

The processes are, in a measure, igneous concentration, 
the separation of the worthless gangue from the valuable 
portion of the ore by oxidation and reduction in the presence 
of heat aided by suitable fluxes and fuel, and taking advan¬ 
tage of the difference in specific gravity of the materials. 

For smelting, we must have ores (or a mixture)*of suitable 
composition, and for its successful operation a sufficient per¬ 
centage of lead, copper, or iron pyrites must be present. 

Ordinarily for lead smelting the charge should contain 
from 12 to 18 per cent, of lead, and for matte smelting not 
less than 15 per cent, of matte should be produced. 


56 


FRASER & CHARMERS 


Large smelting companies buy ores of all kinds, even 
those containing neither lead nor copper, afterward combining 
them with copper or lead ores, as the case may be, in such 
proportion as to produce a charge containing the proper 
amount of copper or lead. 

Often ores to be smelted are previously roasted in order 
to minimize and therefore concentrate as much as possible 
the matte production. 

In “pyritic” smelting no previous roasting is performed. 

The slags produced in smelting consist, to the extent of 
about 90 per cent., of silica, ferrous oxide and lime, the other 
10 per cent, being alumina, oxide of zinc, etc.; hence it will 
be seen that for smelting not only a proper percentage of lead 
or copper must be present, but also silica, iron and lime. 

As the metals or their compounds to be recovered usually 
have a quartz gangue, limestone and iron ore are usually the 
fluxes required, and they should be found in a locality con¬ 
venient to the smelter. 

The fuel used in blast furnaces is coke, charcoal, or a 
mixture of the two, in amounts equal to about one-sixth of 
the weight of the ore and fluxes: I11 reverberatories, wood, 
coal, gas or oil is used. 

All ores of copper or lead can be smelted, and when 
they contain too low a percentage of these metals to be 
smelted directly, they can be brought up to the standard of 
smelting ores, by previous concentration. 

Ores containing any considerable quantity of sulphur 
should be previously roasted, as they will then require less 
iron flux and the capacity of the furnace will be correspond- 
inglv increased. Such ores can often be roasted without 
previous crushing, in heaps, stalls, or kilns, at small expense; 
after which they can be satisfactorily smelted. The oxides 
and sulphides re-act upon each other in the furnace 
with the production of metallic copper or lead and sul¬ 
phurous acid gas. 


57 


FRASER & CHALMERS 


Success in smelting (outside of smelting carbonates of lead 
and copper, which are very simple operations) depends upon a 
proper mixture of ores, proper roasting and adjustment of 
fluxes. The mere presence of a little galena in a camp is 
not sufficient to justify the erection of a smelting plant. For 
good results, a mixture of ores is usually needed, high grade 
silver and gold ores to bring up the value of the bullion; ores 
with lime gangue to neutralize ores in quartz so as to avoid 
if possible melting barren fluxes; reasonable transportation to 
market of bullion, cheap fuel, and many smaller consider¬ 
ations, important in influencing commercial results. 

The cost of smelting varies greatly according to the char¬ 
acter of the ore, size of the furnace, arrangement, locality, etc. 

Smelting practically saves all the gold, 95 per cent, of the 
silver and 90 per cent, of the lead or copper. 

Blast furnace slags do not usually contain more than 
of one per cent, of lead or copper and % oz. silver to the ton. 

The type of slag to make and the percentage of valuable 
metals contained therein is more of a commercial than a 
metallurgical problem. 

Not an unimportant advantage of smelting is, that all 
ores in proper combination can be treated by this process. 
To conduct the process successfully, high metallurgical 
ability and experience are required, for it is much more 
complicated than other metallurgical processes, such as 
amalgamation, leaching, etc. 

FRASER & CHALMERS EMPLOY EXPERIENCED 
PROFESSIONAL MEN IN ALL THEIR DEPART¬ 
MENTS, AND WHEN ORDERS ARE RECEIVED 
THEY ARE FOLLOWED THROUGH THE DRAW¬ 
ING ROOM AND SHOPS BY THE EXPERT TO 
WHOSE DEPARTMENT THEY BELONG, THUS 
INSURING ACCURATE AND PROMPT ATTEN¬ 
TION. t 


58 


FRASER & CHALMERS 


PYRITIC SMELTING 

Theoretically, pyritic smelting is the process of smelting 
sulphide ores in a blast furnace without the aid of carbona¬ 
ceous fuel, heat for smelting being furnished by the com¬ 
bustion of the sulphur in the ore. 

Practically, some advantage is taken of this source of 
heat aided by a moderately hot blast, and the percentage of 
carbonaceous fuel has been thereby much reduced, though 
not altogether avoided. Dr. Peters calls this modification 
and practical use of the process “compromise pyritic smelt¬ 
ing’ 1 . It may be defined as smelting with from 3 to 4 per 
cent, of coke, using a hot blast, low pressure and a large vol¬ 
ume of air. Excellent results are obtained with a blast 
heated to only 400° Fahr., though as hot as iooo° would be 
preferable. 

Any ordinary copper matting furnace is suitable for this 
work ; it should have high jackets, preferably of steel, be pro¬ 
vided with a brick or iron hood, the blast should be trapped, 
and the slag and matte should discharge continuously into 
a forehearth. 

By this process as high a concentration as 13 into 1 may 
often be obtained. 

This process has been employed with only enough cop¬ 
per present—about one-half of 1 per cent—to clean the slag. 
The presence of some copper in the ore is essential, otherwise 
there will be considerable loss of gold and silver in the slag. 

Compromise pyritic smelting is also successfully applied 
to smelting copper ores containing as little as 5 per cent of 
copper,—a 30 per cent, copper matte being produced. From 
2 E* t° 3 per cent, of coke is used and a blast heated to 400° 
Fahr.; the matte is run through again, producing a 50 to 60 
per cent, matte. The best result so far in the direction of 
pyritic smelting is the work of Mr. Robert Sticht, General 
Manager of the Mt. Lyell Mining & Railway Co., Tasmania. 


59 



FRASER & CHALMERS 


IRON MATTE SMELTING 

This process is often classed under pyritic smelting. It 
consists in smelting dry sulphide ores which should contain 
not less than 15 per cent, of iron pyrites, with from 10 to 20 
per cent, of coke, a cold blast being used. As in compromise 
pyritic smelting, to obtain clean slag some little copper 
must be present. 


METHOD OF HEATING THE BLAST 

The blast is best heated by causing it to pass through a 
series of large cast-iron “U” shaped pipes contained in a 
brick structure, the tubes being heated from fire-boxes in 
which wood is burned. Should the blast be heated to a high 
temperature, the blast pipe and bustle pipe should be lined 
with brick. 

Attempts have been made to heat the blast by means of 
hot slag, also by air jackets ; the former method requires 
considerable machinery such as hydraulic mechanism for 
propelling the pots of slag through a chamber or tunnel, and 
in the latter, there is not sufficient superficial heating area. 

It has been suggested that oil be burned in a chamber 
placed between the blower and the furnace, and that the 
blast pass through the chamber, being thereby heated. We 
think that the weakening of the effectiveness of the air by 
mixing it with the products of combustion from the oil 
much more than counterbalances any advantages sought to 
be gained by this method of heating. 


60 


FRASER & CHALMERS 


S. E. BRETHERTON’S PATENTED SYSTEM FOR 

HEATING BLAST 

Air. S. E. Bretherton, of Silver City, New Mexico, has 
recently introduced a method for heating the blast by means 
of heat radiated from blast-furnace slag, and by this means 
he states that he has succeeded in largely reducing the per¬ 
centage of coke and very materially increasing the capacity 
of the furnace. 

Plates 931 and 932 show the construction and arrange¬ 
ment of the apparatus which he is using. The furnace is 48 
inches in diameter, and has one single-welded steel jacket 
9 y 2 ft. high (plate 931 shows this jacket). The blast is 
trapped, and the slag and matte flow continuously over a 
jacketed spout into a forehearth or settler placed within a 
brick chamber. 

The forehearth is large, compared with the size of the 
furnace, to permit the slag to separate from the matte. The 
slag flows from the forehearth continuously, and the matte is 
tapped at intervals from the bottom spout. 

Placed over the foreliearth is a large rectangular sheet- 
iron box which has vertical flues passing through it, the 
larger portion of the box being directly over the forehearth. 
The heat radiated from the molten slag passes upward through 
those flues situated directly over the forehearth, then down¬ 
ward through the others, after which it passes under and 
around the forehearth and out through the chimney, as indi¬ 
cated by arrows. 

The rectangular box is placed between the blower and 
the wind-box of the furnace and the blast is made to traverse 
twice through the box, by means of a vertical diaphragm 
contained in the same. 


61 


FRASER & CHALMERS 


rO 

CT\ 

V 



62 


S. E. Bretherton’s Patented System for Heating Blast. 













































































































































































Plate 932 


FRASER & CHALMERS 



63 


. E. Bretherton’s Patented System for Heating Blast 












































































































FRASER & CHALMERS 


The small door in the brick wall over the forehearth is 
for the introduction of sticks of wood for keeping a small 
fire on the surface of the slag; this is sometimes desirable, 
and assists in heating the blast. 

By means of this simple apparatus Mr. Bretherton reports 
that he is enabled to heat the blast to from 500° to 6oo° 
Fahr., and thereby make a saving of from one-half to two- 
thirds of the amount of coke required when the furnace is 
run in the ordinary way with cold blast, and also increases 
the capacity of the furnace more than 60 per cent. His fur¬ 
nace formerly smelted 50 tons of ore, it now smelts 80 tons ; 
he formerly used from 10 to 15 per cent, of coke, he now 
uses from 3 to 8 per cent., the ore being practically the same 
in both cases. 

This valuable blast furnace accessory can be applied to 
any copper, lead or iron matte smelting furnace which is 
large enough to yield a continuous flow of slag. 

Parties who are engaged in smelting and wish to save 
fuel and increase the capacity of their furnaces, would do 
well to write to us for further particulars and estimates. 


64 


FRASER & CHARMERS 


BLAST FURNACES 

BLAST FURNACES FOR LEAD ORES 

The general form of the blast furnace used for smelting 
silver-lead ores has undergone but little change during the 
past few years, improvements having been only in minor 
details and in the direction of simplicity and durability. 

The principal changes have been the extensive substitu¬ 
tion of sheet-steel jackets and structural-steel mantle or sup¬ 
porting-frame, for such parts as were formerly made of cast iron. 
In fact, in addition to the four columns used for supporting the 
brick shaft, very little cast iron enters into the construction of 
the modern blast furnace. 

This change in construction makes the first cost of the 
furnace greater, but this is more than compensated for by its 
increased durability (which is especially important in remote 
localities) and by decreased weight. 

In general, the blast furnace for lead ores may be 
described as a rectangular brick shaft bound with iron, 
resting on a steel mantle-frame supported at the four 
corners by cast-iron columns. Below this shaft is the 
smelting zone, which has a bosh surrounded by water jackets 
made of boiler-steel plates or of cast iron; the side jackets 
near the bottom have openings for tuyeres; the jackets rest 
on a curb of fire-brick encased in steel plates, and in the 
center of this curb is a large cavity called an internal crucible 
from which the lead is removed through what is known as 
“ Arent’s Syphon Tap”. 

Round water-jacketed furnaces are employed when smelt¬ 
ing operations are conducted on a small scale, in refineries 
for working up by-products, for jewelers’ sweepings and in 
experimental laboratories. 


65 


Plate 875 


FRASER & CHALMERS 



Vertical Sectional View 


Steel Water=Jacketed Blast Furnace For Lead Ores 

Round Type 

To avoid confusion in Illustrating the details of the furnace, the cast-iron supporting 

columns have been omitted from the cut 


66 












































































































































FRASER & CHALMERS 


STANDARD 36HNCH STEEL WATER=JACKETED BLAST 
FURNACE FOR LEAD ORES (Round Type) 

Plate 875 illustrates a vertical sectional view of our 
standard design for round lead furnaces which we make in 
several sizes—from 20 inches diameter upwards. The curb 
is made of tank steel plates, the jackets of boiler steel ; the 
brick shaft is surrounded with a steel casino:. 

Plate 796 is a photo-reproduction showing the curb and 
jackets of the same furnace. The projection on the left is 
the lead-well which, as well as the curb, should be lined with 
fire-brick. 

As the smelting capacity of these round furnaces is lim¬ 
ited bv their diameter at the tuyeres, and as it has been 
found by experience that this diameter cannot exceed 48 
inches, recourse must be had to oblong rectangular furnaces 
when smelting to any considerable extent. 

THE SIZE OF A FURNACE is determined by the internal 
area at the tuyere level. With oblong furnaces the width varies 
from 30 to 42 inches, and the length from 60 to 160 inches. 
Furnaces have been built 60 inches wide, but the tuyere 
pipes were then pushed into the furnace 6 inches beyond the 
inner wall of the jackets, which reduced the actual width 
between the tuyeres to 48 inches. No advantage was gained 
by thrusting the tuyere pipes (which had to be water-jacketed) 
into the charge, and the construction was abandoned. 

As the width of the furnace is increased, a proportionately 
higher blast pressure is required, as there is more material to 
force the air through ; there should also be a corresponding 
increase in the height of the shaft. 

The distance from the tuyeres to the feed-floor is desig¬ 
nated as the height of the furnace, and this may vary from 
12 to 18 feet. 


67 


FRASER & CHALMERS 


Tuyeres are placed on the sides only, one at the back end 
being seldom used; as a rule, there should be one 3-inch 
tuyere or its equivalent for every 2 sq. ft. of furnace area at 
the tuyere level. 

The lower part of the brick shaft is made thicker than 
formerly, in order to reduce radiation of heat and lessen fuel 
consumption. The shaft is either lined with, or built entirely 
of, fire-brick. 

BLAST FURNACE FOR LEAD ORES (Rectangular Type) 

Plate 775 is an illustration of a modern blast furnace 
for silver-lead ores. The jackets are of flange steel, the 
seams being welded together ; the curb is of tank steel, 
the mantle-frame of structural steel. Pockets cast on the 
columns receive the overflow water from the jackets. The 
only cast-iron parts entering into the construction are the 
columns and spouts. 

As a rule, modern lead furnaces do not extend above the 
feed-floor, though lately we have filled orders for some in 
which the shaft extends above the feed-floor several feet, 
where it is capped with a steel hood from which extends a 
steel stack and a downtake. 

In those furnaces which do not extend above the feed- 
floor the fumes are conducted into the dust chamber through 
an iron or brick flue, which starts from the furnace shaft just 
below the feed-floor and extends in a downwardly inclined 
direction into the dust chamber, the latter being usually built 
in back of the retaining wall, this wall forming the front 
wall of the dust chamber. 


68 


FRASER & CHALMERS 


Plate 775 



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11 i ' > ' ; ; 11 


Steel Water=Jacketed Blast Furnace for Lead Ores 

Rectangular Type 


69 



























































































































































































































































































































































































































































FRASER & CHALMERS 


Plate 796 



Curb and Jackets of Standard 36=inch Steel Water=Jacketed 
Blast Furnace for Lead Ores (Round Type) 

(See page 67.) 


70 







FRASER & CHALMERS 


BLAST FURNACES FOR COPPER ORES 

These furnaces differ considerably from those used for 
lead ores. Small ones, up to 48 inches in diameter, are made 
round; larger ones, oval and rectangular. 

The jackets are made of steel plates and are of greater 
height than those used for lead. The internal crucible is either 
very shallow or dispensed with altogether. The curb is low 
and rests upon a cast-iron base-plate supported on columns. 
Plate 80 represents an exterior view of our improved round 
blast furnace, a style extensively used for smelting copper 
ores and for concentrating matte. Plate 859 is a vertical 
sectional view of the same furnace. 

The jacket is made of the best flange steel, the sheets 
being either riveted or welded together, as preferred (see 
“Water Jackets”), and fitted with bronze tuyeres. The 
jacket is surrounded with a removable wind-box; to this the 
blast pipe is connected, an arrangement insuring equal dis¬ 
tribution of the blast to each tuyere and hence a perfect 
delivery of air to every part of the charge, thereby producing 
a very uniform melting zone. The tuyeres being entirely 
within the water space of the jacket, are protected from the 
action of the heat and consequently do not burn out or cause 
any trouble whatever. Peep-holes with removable mica 
coverings are placed in the wind-box opposite the tuyeres. 

The curb is a sheet-steel casing made by prolonging the 
outer plate of the jacket some distance below the water space. 
The curb rests on a cast-iron base-plate which is supported 
on four columns. There is a large circular opening in 
the center of the base-plate, closed by two drop doors 


/ 


71 


FRASER & CHALMERS 



Vertical Sectional View 


Steel Water=Jacketed Blast Furnace For Copper Ores 

Round Type 


72 






























































































Plate So 



Steel Water=Jacketed Blast Furnace for Copper Ores 

Round Type 


73 
























































































































































































































































































































































































































FRASER & CHALMERS 


attached to its under side. The whole structure is complete 
with stack, inlet and outlet water pipes, slag and matte 
spouts, and the jackets are equipped with blow-off pipes and 
convenient hand-holes. 

The furnace requires only a few fire-bricks to line the 
curb and base-plate after which “steep”, a mixture of fire¬ 
clay and coke dust, is tamped in, and cut out to form a cruci¬ 
ble of the proper shape. 

These water-jacket furnaces are superior to all others in 
simplicity, strength, perfection of water circulation and 
capacity. They will run for months without a stoppage. 

For low-grade pyritic ores the larger of these furnaces 
may be used without an internal crucible, the materials as 
soon as they reach the bottom in a molten condition being 
permitted to flow out of the furnace into an exterior crucible 
or forehearth mounted on wheels; this forehearth may be either 
water-jacketed, or lined with fire-brick. 

We sell very many of these excellent furnaces, and by 
reason of their simple construction, facility with which they 
can be erected, durability and other desirable qualities, 
find great favor among our customers. 

We might state here that the 36-inch furnace, which is 
the size most in demand, weighs 10,700 pounds, requires 
about 1,000 gals, of water per hour, and has a capacity of 
from 25 to 50 tons per 24 hours. 


74 


FRASER & CHALMERS 


LARGE RECTANGULAR COPPER FURNACE. 

Plates 923, 924 and 925 show vertical, end and side sec¬ 
tional elevations of a 44 x 168 in. steel water-jacketed blast¬ 
furnace for copper ores recently designed and built by 
Fraser & Chalmers. 

This is the largest blast furnace for copper ores in exist¬ 
ence, and embodies all the features of the best modern prac¬ 
tice. 

The curb, made of sheet steel, rests on a cast-iron base¬ 
plate built in sections for convenience in transportation ; the 
plate rests on eight short columns and has three openings 
covered by double drop doors. 

To the center of one side of the curb is attached a tymp 
jacket and a jacketed spout, so constructed that the blast will 
be trapped and the matte and slag flow in a continuous stream 
over the spout into a capacious forehearth in which a separa¬ 
tion between the materials mentioned will take place. 

There are six side and two end jackets, made of flange 
steel; they are seven feet in height, the side jackets only, being 
“boshed”. 

There are twenty tuyeres, ten on each side, each having 
an independent tuyere-box fastened air tight to the jacket 
and rigidly connected with the bustle-pipe ; each tuyere pipe 
is fitted with a blast gate. By this construction all leakage 
is prevented and the amount of air entering each tuyere can 
be nicely regulated. 

On each side of the furnace there are three charging doors 
which extend the full length of the furnace, so that wall 
accretions can be readily reached. The brick shaft extends 
eight feet above the charging floor, at which point it is sur¬ 
mounted by a steel hood, stack and downtake. 

This furnace is not only of the most modern type, but it 
is of great durability and of very great capacity. 


75 


FRASER & CHALMERS 


Plate 925 



•=2—fX' 1 


«- L / 


i 








Large Steel Water=Jacketed Blast Furnace for Copper Ores 

Rectangular Type 


Sectional View of End 


76 




























































































































































































































FRASER & CHALMERS 


Plate 924 



Large Steel Water=Jacketed Blast Furnace for Copper Ores 

Rectangular Type 

Sectional View of Side 


77 











































































































































































































































































































































Plate 923 



Large Steel Water=Jacketed Blast Furnace for Copper Ores 

Rectangular Type 

Sectional View of Side, showing portion of Stack and Downtake 

78 

































































































































































































































































Plate 854 


FRASER & CHALMERS 



79 




Large Steel Water=Jacketed Blast Furnace for Copper Ores 

Oval Type 




























































































































































































































































































































FRASER & CHALMERS 


STEEL WATER-JACKET COPPER FURNACE 

Oval Type 

Plate 854 illustrates a 42 x 120 in. oval blast furnace 
used for matting copper ores. The jacket and curb are made 
in one piece, the jacketed portion being ft- high. The 
tuyere pipes are rigidly connected with the wind-box and the 
jacket, and each tuyere has an independent blast gate. The 
base-plate has two sets of drop doors. The feed-floor is on a 
line with the top of the jacket; above it, a brick shaft ex¬ 
tends through the roof of the building, the shaft resting on 
a mantle frame supported on columns. It is of the latest de¬ 
sign and embraces many desirable features. 

WATER JACKETS 

The smelting zone of the blast furnace is surrounded by 
water-cooled shells called “ water jackets”, made of cast-iron 
or steel plates ; in the latter case the plates are flanged, the 
edges riveted or welded together, and so constructed that no 
seam is exposed to the fire. 

Jackets have been made of cast steel, but they are difficult 
and expensive to make and, as their cost is not warranted by 
a proportionately increased durability over those of cast iron, 
their use has been abandoned. 

The average height of jackets for lead furnaces is 42 
inches, for copper furnaces from 4J2 to 6 ft., while for iron 
matte smelting we have made them as high as 8 ft. 

In rectangular furnaces the number of jackets depend 
upon their size—two end and two side jackets being the usual 
number except when the furnace is long; in this case the side 
jackets are made in two or three sections, for convenience in 
handling. 

When it is desired to jacket a furnace to a considerable 
height, the jackets are often made in two tiers, which permits 
of making them smaller, consequently easier to handle. 

A common method of “jacketing” cast-iron tapping 


80 



FRASER & CHALMERS 


jackets and spouts is to place in the mold a wrought iron pipe 
bent to suit the shape and pouring the molten iron around it. 

We make a specialty of “SECTIONAL” steel jackets 
for mountain transportation, no piece exceeding 350 pounds 
in weight. When jackets are of such size and shape that 
they cannot be sectionalized, as is the case with round 
copper furnaces, we ship the plates cut, punched, rolled and 
nested, to be riveted together at the mine. 

All jackets made by us are carefully tested before they 
leave our shops ; they are provided with all necessary hand¬ 
holes, tuyere openings, lugs and binders, and connections for 
water piping. 

ADVANTAGES OF STEEL JACKETS 

Cast-iron jackets are still used for lead furnaces, but for 
copper and pyritic furnaces, steel ones are usually preferred. 
As before stated, the tendency is to abandon cast-iron con¬ 
struction in blast furnaces except for the columns which sup¬ 
port the brick shaft. The substitution of steel gives in¬ 
creased strength with less material and minimizes the danger 
of breakage and delay incident to cast-iron construction. 
Lighter construction means less freight charges to pay—an 
important item in the installation of a smelter. 

We know of some of our steel jackets which have been in 
constant service for five years and are as good now as the day 
the furnaces were “blown in”. 

On the other hand, a cast-iron jacket may crack the first 
day it is used ; they are a constant source of annoyance and 
loss of time, and necessitate carrying a considerable stock of 
extras. 

STEEL JACKETS FOR ROUND FURNACES 

Plate 796 (page 68) represents the construction and general 
appearance of a set of steel jackets for a 36-in. round lead 
furnace, the set being made in three pieces and the seams 
riveted together; the jackets rest upon a curb made of tank 
steel. 


81 


FRASER & CHAEMERS 


Plate 794 shows a set of “sectional” steel jackets for a 
36-in. furnace, made in seven pieces, for muleback transpor¬ 
tation. The seams of these jackets are welded together by 
our new process, a process that has been endorsed by the 
leading smelting men. 

Plate 859 shows the construction and general appearance 
of a single jacket for a 36-in. copper furnace; the plate 
shows the steel sheets riveted together, but we also make it 
with welded seams. This is a most popular furnace and 
admirably meets the requirements of parties who wish to 
smelt on a limited scale. There is scarcely an important 
copper camp in the United States or Mexico where one of 
them cannot be found in operation. 

Plate 795 shows the welded steel jacket of a Bretherton 
48-in. copper furnace. The jacket is made with a bosh and 
is 9 )/ 2 ft. high by 5 ft. inside diameter at the top and 48 in. 
diameter at the tuyeres. The Silver City Reduction Company, 
of Silver City, New Mexico, has two such furnaces in blast. 
The following letter from their manager, Mr. S. E. Breth¬ 
erton (from whose sketches we designed and built the 
furnaces) is convincing evidence that they have been emi¬ 
nently satisfactory : 

Silver City, New Mexico, Feb. 27, 1S99. 

Gentlemen: In reply to yours of the 22d inst., asking about the Fraser 
& Chalmers Welded Water Jacket Blast Furnace, will state that we have 
had one of them in use three years, and another more than two years, where 
we have the worst water for forming scale I ever knew. We wash the scale 
out at the bottom of the furnace about every thirty days, and to-day the 
furnaces are both as good as the day we purchased them, and so far we have 
not had to purchase a fire-brick or pound of fire-clay for repairs, on account 
of their shape, and the water jacket being as high as the feed-floor. 

We are now smelting with one of the round furnaces, doing very clean 
work, 60 to 80 tons of ore and some flux, not including the fuel we are using. 

Hoping the above answer to your question will be satisfactory, 

Yours truly, 

SILVER CITY REDUCTION COMPANY, 

S. E. Bretherton. 


82 


Plate 794 


FRASER & CHALMERS 



83 


Set of Sectional Welded Steel Water Jackets for a Round Lead Blast Furnace 








FRASER & CHALMERS 


Plate 795 



Seamless Sheet=Stee! Water Jacket for a 48=inch Copper 

Furnace. Bretherton Design 


84 







Plate 792 


FRASER & CHALMERS 



85 


Riveted Steel Water Jackets for a Lead Blast Furnace 




Plate 793 


FRASER & CHALMERS 



86 


Welded Steel Water Jackets for a Lead Blast Furnace 








Plate 791 


FRASER & CHALMERS 



87 


Welded Steel Water Jackets, 8 feet high, for a Copper Blast Furnace 






FRASER & CHALMERS 


Plate 885 







Cast=Iron Jackets for a Lead Furnace 


88 






































































































FRASER & CHARMERS 



Plate 917 shows a design of individual tuyere-box which 
we furnish with large smelting furnaces. It is of cast iron, 
is bolted air tight to the water jacket and rigidly connected 
with the bustle pipe. It is provided with a large door having 
a mica-covered observation hole. In the lower part of the 
tuyere pipe there is a blast gate. 

With this construction leakage of air is impossible, and 
the amount entering each tuyere can be nicely regulated. 


89 































FRASER & CHALMERS 


FURNACE CAPACITY 

The capacity of a furnace depends chiefly upon the 
amount of fluxes necessary, the fusibility of the charge and 
the pressure and volume of the blast. Any considerable 
quantity of fine material will lessen the capacity. 

Although only roughly approximate, the following will 
suffice as a basis for computation of capacity under ordinary 
conditions. A furnace will smelt some 2^ tons of ore, or 3^ 
tons of ore and fluxes, per 24 hours for each square foot of 
area at the tuyeres. Large furnaces always work better 
than small ones and have a proportionately greater capacity. 
With carbonate ores a greater capacity will be attained. 

When parties write to us for estimates on smelting 
furnaces and smelting plants, answers to the following 
questions will be of great service to us in preparing replies: 

(1) The kind of ores to be smelted—copper or lead. 

(2) Character of the ores. Send small pieces represent¬ 
ing average character. 

(3) Analyses and assays of the ore. 

(4) Number of tons of ore to be smelted per 24 hours. 

(5) If we are to quote price for a complete smelting 
plant, it will be necessary for us to know whether sampling 
machinery will be required, the percentage and kind of ores 
to be roasted ; also final products. 

(6) Should waterpower be available, head or fall in feet 
and cubic inches flow should be given. 

(7) Should drawings be necessary, a rough sketch show¬ 
ing contour of the ground where smelter will be placed 
should be sent. 


90 



FRASER & CHALMERS 


(8) Is the machinery to be of regular design, or to be 
made sectional for mule-back transportation ? 

Any other available data suggested by unusual conditions 
or requirements should be included, always bearing in mind 
that we shall be able to cover the requirements of the cus¬ 
tomer with a saving in time proportionate with the complete¬ 
ness of their answers to the foregoing questions. 

The smallest furnace for copper or lead ores made by us 
has a diameter of 20 in. at the tuyeres and a capacity of 
some eight to twelve tons per twenty-four hours (a size 
smaller than this would be neither practicable to build nor 
at all satisfactory to operate). This size is used in metal¬ 
lurgical laboratories for making trial runs, also for smelting 
rich ores and jewelers’ sweepings, but it is not well adapted 
for constant daily running at a mine. 

Our next larger sizes are 24, 30, and 36 in. for either copper 
or lead, and 42 and 48 in. for copper ores. All of these are 
suitable for constant use. 

With 48 in. the maximum diameter at the tuyeres has 
been reached ; larger furnaces are of the rectangular type, of 
which we make all sizes from 33 x 60 in. to 44 x 168 in. 


FRASER & CHALMERS ACT AS PURCHASING 
AGENTS FOR MINING COMPANIES. S S & J* 


91 


FRASER & CHALMERS 


BLAST FURNACE ACCESSORIES 


BLOWERS 

For supplying- blast to smelting furnaces of small size, 
either a fan or a pressure blower can be used. The fan 
possesses the advantages of cheapness and in not requiring 
much power ; when it is used it is best to have it mounted 
on an adjustable bed with a combined countershaft. 

For large furnaces, pressure blowers are employed, usually 
the Green, Root or Connersville blower; all are two-impeller 
machines and constructed on more or less the same principles. 

When the selection of a blower is left to us, we recom¬ 
mend the Green for use in connection with smelting furnaces, 
as we consider it the best blower in use. 

We furnish the Root, or Connersville blower, when our 
customers are prejudiced in favor of these makes. 


92 


FRASER & CHALMERS 


Plate 86r 



STANDARD GREEN BLOWER 

The above cut shows a Standard Green Blower with dis¬ 
charge outlet on either side. Blowers with discharge outlet 
at top or bottom are also kept in stock. Blowers with verti¬ 
cal engines or electric motors on same bed plate made to 
order. 

The inlet and outlet flanges are tapped for tap or screw 
bolts and provided with loose flanges for attaching light sheet 
iron pipe. 

A mercury pressure gauge is supplied with each blower. 

Note. —Standard Blowers of a size smaller than No. i, 
have one set of gear wheels and bearings cast on head plate. 


93 






























FRASER & CHALMERS 


Plate 863 



Sectional View 


THE GREEN BLOWER 

The working parts are two perfectly balanced impellers, 
each of which is a single strong easting, well ribbed inside 
and firmly fastened to a steel shaft of ample dimensions, 
extending the full length of blower. The journal bearings 
are bushed with phosphor bronze and are detachable from 
blower, being bolted and dowelled to the head plate, easily 
removed and returned to their original central position. 

The blower is geared at both ends, the gearing being of 
ample proportions, cut in the most accurate manner, and 
enclosed in an oil-tight cover, free from dust and dirt, and 
continuously in oil. The casing of the blower is well pro¬ 
portioned, strongly ribbed and firmly bolted together. 

The head plates, in addition to being well ribbed, are 
further strengthened by making the hoods or extensions, into 
which the circular ends of the impellers project, a part of 
head plate casting. The circular parts of casing and the 
pipe plates are also ribbed, and the pipe plates are fitted be¬ 
tween and bolted to the head plates and circular casing. 

In addition to the strength imparted to it by its being 
firmly ribbed, the casing is firm and rigid by reason of its 
proportionately short length, which is much less than that of 
any other two-impeller blower of the same displacement. 


94 

















FRASER & CHALMERS 

Plate 864 



COMPLETE IMPELLER 

The impeller is a single casting with a steel forged shaft. 
Two such pieces compose the interior working parts of 
blowers and exhausters. 

The finished surfaces of the impellers are two circles, 
which roll together without friction, forming an even and 
continuous practical contact; the point of contact being 
always on the pitch line of the gears and traveling at the 
same speed at all points during the revolution. 

In order to give additional strength to the impellers, and 
also as a protection in case the journals should become 
worn, the ends of the impellers are provided with circular 
heads or disks, which heads are part of the impeller casting. 
These heads or disks are truly turned, so that in case the 
journals should wear, the heads of the two impellers will roll 
together without friction and prevent the bodies of the 
impellers from coming into actual contact. 

The gear wheels are keyed to the shafts close to ends of 
journal bearings, forming collars at each end of blower and 
preventing the impellers from rubbing endwise against the 
interior sides of head plates. 

These provisions insure an entire absence of internal 
friction at all times, and are a positive preventive of accidents 
which might otherwise occur. 

Note. — In all other two-impeller blowers, the peripheries 
of the impellers sweep or slide past each other, the contact 
surface of one impeller traveling faster than the contact 
surface of the other with an irregular, uneven contact. 
As there is no provision for preventing the impellers of 
such blowers from moving endwise, or from coming into 
actual contact, in case of wear to the journals the result is a 
large amount of internal friction and possible breakage of 
the impellers. 


95 



DIMENSIONS, WEIGHTS, CAPACITIES AND POWER 


FRASER & CHALMERS 


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96 


























































Plate 862 


FRASER & CHALMERS 



97 


Standard Green Blower 

With Vertical Engine attached to the same Bed=Plate 





























FRASER & CHALMERS 


STANDARD GREEN BLOWER 
With Vertical Engine Attached to the Same Bed=Plate 

Plate 862 shows a blower directly connected with a 
vertical engine, both being bolted to the same bed-plate, 
which is often a desirable arrangement when only one or two 
blowers are used. When, however, a number of blowers are 
to be used, the best and most economical arrangement is to 
drive them together by one high duty engine, a duplicate 
engine being kept in reserve. 


FRASER & CHALMERS FURNISH COMPLETE 
PLANTS FOR BESSEMERIZING COPPER 
MATTE, FOR COPPER REFINING AND FOR 
THE DESILVERIZATION OF LEAD BULLION, 


98 


Plate 845 


FRASER & CHALMERS 



99 


Settling Pot 











Plate Soi 


FRASER & CHALMERS 



100 


Forehearth 









Plate 790 


FRASER & CHALMERS 



101 


No. 8 Slag Pot with Anti=Friction Roller Bearings 


FRASER & CHALMERS 



102 































FRASER & CHALMERS 


FOREHEARTHS 

By the use of the forehearth a separation of matte or 
metal from slag is obtained outside of the furnace; it is 
in fact an exterior crucible. 

For small furnaces, a large Settling Pot (Plate 845) can 
be conveniently used for this purpose. The pot is provided 
with two spouts so that when one slag pot is filling another 
can be placed in position; they are of such height that the 
bowl of the ordinary slag pot will pass beneath them; the 
wheels are provided with roller bearings. 

For large furnaces, correspondingly large forehearths are 
used; they are usually rectangular boxes of cast iron lined 
with fire-brick and mounted on four wheels (see Plate 801). 

They are also made with steel-jacketed sides and cast-iron 
bottoms. 

In large copper-smelting plants where matte is bessemer- 
ized, stationary forehearths holding as much as 10 tons are 
sometimes used; from these the matte is tapped either directly 
into the converter or into a ladle handled by an electric 
crane. 

Recently a large tilting forehearth has been introduced, 
which is somewhat similar to the tilting steel furnace, the 
tilting being performed by hydraulic mechanism. 

SLAG POTS 

Plate 790 shows our Standard No. 8 Slag Pot, which is 
used by many smelting companies. The wheels are fitted 
with anti-friction roller bearings, and it is made throughout 
to withstand rough usage. The complete slag pot weighs 
500 lbs., the bowl separately 290 lbs; capacity, 2 cubic feet. 


103 


FRASER & CHALMERS 


Another desirable form of slag pot is shown in Plate 856. 
The construction is somewhat lighter; the wrought-iron leg 
and handle are made in one piece, riveted with hot rivets to 
the lug cast on the bowl; the spokes are of flat steel, the hub 
being cast around the inner ends while the outer ends are 
bent at right angles and riveted to the steel rim. This is an 
excellent pot and capable of long service. 

We make slag pots of several other designs for special 
service, such as litharge pots, the bowls of which are flat on 
the bottom and detachable from the carriage. 

We also make slag pot bowls of a special foundry 
mixture, which we call “semi-steel 1 ’, which is much less 
liable to crack than cast iron; its use permits of lighter con¬ 
struction. 

A cast-iron button (see Plate 926), is sometimes inserted in 
the bowl to receive the splash from the molten slag. 


COPPER BULLION POT 

Plate 876 shows our Copper Bullion Pot mounted on 
wheels provided with roller bearings. Weight of the mold 
and carriage complete 700 lbs.; weight of the mold 525 lbs. 

This pot is also made with lugs projecting from the bottom 
and sides of bowl around which wrought-iron bands are 
shrunk (see Plate 927), thus preserving its usefulness should 
cracks appear in the bowl after long usage. 


104 


FRASER & CHALMERS 





105 



























































FRASER & CHALMERS 


Plate 927. 



Plate 926. 



Slag Pot 

Section of bowl showing the application of splash button. 


106 















































FRASER & CHALMERS 


Plate 836 



SCALES FOR WEIGHING FURNACE CHARGES 

These scales are made in the most substantial manner. 
They have four or more brass beams, each separate from the 
others ; 1,500 pounds can be weighed on each beam by 5 
pounds. 

After being adjusted the beam box can be closed and 
locked, thus placing it entirely beyond the control of the 
workmen. 

We also furnish all other scales used in the treatment of 
ores, viz.: Moisture Scales, Wheelbarrow Scales, Dormant 
Warehouse Scales, Railroad Track Scales, etc. 


107 






















































































































FRASER & CHARMERS 


Plate 901 



Steel Charging Barrow 


Plate 902 



Two=Wheel Coke Barrow 


108 






































































































































































FRASER & CHALMERS 


Plate 903 



TUBULAR STEEL TRAY BARROW 


With smelting equipment we furnish Charging Barrows, 
Coke Barrows and Tray Barrows, all made of steel and of the 
best construction to stand hard usage. 

The Charging Barrow with plain or with anti-friction 
roller bearings weighs 575 pounds and has a capacity of 10 
cubic feet. 

The Two-Wheel Coke Barrow weighs 220 pounds and 
has a capacity of 10 cubic feet. 

The Tray Barrow usually furnished weighs 109 pounds 
and has a capacity of 6 cubic feet. 

We also furnish smaller barrows. 


109 


















FRASER & CHARMERS 


LEAD MOLDS 

These are made of cast iron, steel or semi-steel, weigh 45 
pounds, and have a capacity of 100 pounds of lead bullion. 
A clean, smooth casting is guaranteed and they are cast with 
the name of the company in raised letters in the bottom. 


FINE BULLION MOLDS FOR GOLD AND SILVER 

These are made of the best iron or steel, absolutely free 
from flaws. Each mold is dressed out and ground smooth 
inside with perfect taper on sides and ends. 


WATER TANKS 

We furnish Water Tanks of wood or steel and of any size 
and style required; large sizes cannot be loaded on cars and 
are shipped knocked down. 


ELEVATORS FOR SMELTING WORKS 

In smelting works of any considerable size there is much 
material, such as slag shells, roasted ore, furnace breakings, 
etc., which require to be smelted, and to raise such material 
from the dump to the charging floor an Inclined Slag Hoist 
or a Platform Elevator is employed. We furnish these 
elevators of a size and construction to suit the requirements. 


FRASER & CHALMERS SUPPLY PUMPS OF ALL 
KINDS AND SIZES USED IN MINING AND MET¬ 
ALLURGICAL PLANTS. STATE YOUR RE¬ 
QUIREMENTS AND OBTAIN OUR ESTIMATES. 


FRASER & CHALMERS 


LARGE SMELTING PLANTS 

The design and arrangement of a smelting plant depend 
upon the nature and magnitude of the work to be done. In 
the selection of a site, such points as the convenient relation 
of the parts, avoidance of hand labor as much as possible, 
disposition of slag, etc., are of paramount importance and 
should receive due attention. Considered from all points, a 
somewhat terraced site is most advantageous. 

A large smelting plant may consist of several depart¬ 
ments, viz.: sampling works, sulphide mill, roasters, blast fur¬ 
naces, steam power, and electric light plants. Connected 
with a lead plant there may be a refinery, and with a copper 
plant, bessemerizing and electrolytic departments, all planned 
according to the magnitude of the works, the character of the 
ores and the products which it is desired to produce. 

Unless a lead smelter is central to the lead market, it sel¬ 
dom has a refinery, and in remote localities copper refining is 
not carried on. 

It is almost essential that a large plant be situated on or 
near a railroad. 

In order to give a comprehensive idea of the general ar¬ 
rangement and construction of a modern silver-lead smelt- 
ing plant, we introduce Plate 906, which shows plan and 
elevation of a 500-ton plant. 

At the sampling plant all ores which require crushing 
are received. Ores which have to be held are stored in the 


FRASER & CHALMERS 


storage bins. Sulphide ores which have to be roasted are 
crushed in the sulphide plant. Ores which go direct to the 
blast furnaces are unloaded at the ore-beds, a small portion 
going to the sampling plant. 

In the space marked u yard” and in the space below it, ores, 
fluxes and fuel are stored ; that portion of the yard next to 
the roasting furnaces is used as a cooling-floor for roasted ore. 

While only a few roasting furnaces are indicated, others 
can be placed on the opposite side of the flue and connected 
with the same. 

Standard and narrow gauge railroad tracks bring all 
points of the plant within easy access. 

The blast furnaces, five in number and of large size, are 
placed in a row and connect with a dust chamber built back 
of a retaining wall; this dust chamber connects with the 
same stack as the roasters. 

The position of the blowers is shown; all deliver air into 
a large main located between the furnaces and the retaining 
wall; they are run by a single Corliss engine, a duplicate 
engine being kept as reserve. 

There is a small engine for running the electric gene¬ 
rator which supplies electricity for lighting and for 
motors which run the platform elevator, slag hoist and an 
electric locomotive which draws the slag cars. One of these 
slag cars, as shown, is receiving its load of molten slag from 
a forehearth. 

In the boiler house there is reserve boiler capacity. 

Small buildings, such as the superintendent’s office and 
laboratory (which are usually built together), store-house, 
blacksmith shop, etc., are not shown. 

The more important buildings are of steel construction. 


112 


Sui||3UIS PK31=49A|IS ujapow 



3SPOH HIO 


906 0;\j{ t i 


TRACK SCALES STD GAUGE TRACKS 
























































































































































































































































































































































FRASER & CHALMERS 


SMALL SMELTING PLANTS 

We introduce Plate 849 to show the general arrangement 
of a small copper-smelting plant; a small lead-smelting plant 
differs from it in very little except in the kind of furnace 
employed. 

Such a plant is best located where a natural difference in 
level of about 12 feet can be secured (this height being the 
distance between the furnace-room and the charging-floor), 
and where there will be a fall-off or slope to the ground in 
front of the furnace, so as to permit of easy disposition of 
slag. 

The building, with the exception of the charging-floor 
and the timbers which form its outer support, may be of 
light construction and is best covered with corrugated iron. 
The engine and blower should be in a room partitioned off 
from the furnace and under a lower roof, while the boiler 
may be under a shed. 

Very little brick-work is required; the blower and engine 
may rest on stone foundations, and, if necessary, a boiler of 
the locomotive type which requires no brick setting, can be 
used. The four short columns which support the furnace 
should rest on a stone foundation. 

The drawings we furnish with such a plant contain all 
details necessary to enable an ordinary machinist and a local 
carpenter to erect the machinery and put up the building. 

The following copy of our standard specifications for a 
30-ton copper-smelting plant gives a description of our 
standard 36-inch, round, steel water-jacketed blast furnace 
for copper ores and all accessories required for a complete 
plant. 


113 


FRASER & CHALMERS 


SPECIFICATIONS FOR A 30 =TON COPPER= 
SHEETING PLANT 

Furnace 

i Steel Water-Jacketed Copper-Smelting Furnace, same as 
shown in Plates 80 and 859, and consisting of: 

1 Water Jacket 36 inches inside diameter at the tuyere 
level by 9 ft. high, made of the best flange steel. The 
jacket to be made in one piece, the seams being either 
riveted or welded together. Jacket to have six tuyeres, 
removable wind-box, hand-holes, inlet and outlet water 
connections. 

1 Cast-iron bottom plate, with two semi-circular dumping or 
drop doors. 

1 Jack Screw for holding these doors in place. 

4 Cast-iron columns for supporting the furnace. 

1 Sheet-steel hood and stack to pass through roof of 
building. 

Blower 

1 Rotary Positive Pressure Blower, having iron impellers and 
top discharge ; speed, 200 revolutions per minute ; dis¬ 
placement per revolution, 15 cubic feet. 

Blast Piping 

All necessary galvanized iron blast piping, three elbows, 
flanges, gaskets, bolts, relief valve and air-gate for con¬ 
necting the blower with the furnace. 


114 


FRASER & CHALMERS 


Furnace Accessories 

1 Howe 4-beam charging scales, platform 43 inches square. 

2 Large settling pots, mounted on carriages, same as Plate 

845; it being intended that these pots be used as fore¬ 
hearths. 

6 Improved No. 8 slag pots, with carriages. Plate 790. 

3 Bullion Pots, with carriages, Plate 876. 

All the above pots to have anti-friction roller bearings. 

1 Steel Charging Barrow. 

1 Two-wheel Steel Coke Barrow. 

6 Tubular Steel Wheelbarrows. 

1 Coke Fork. 

1 Scoop Shovel. 

6 Long-handled Steel Shovels. 

2 Sledges with handles. 

300 lbs. steel furnace bars, assorted lengths and sizes. 

Engine 

1 8x10 inch horizontal self-contained slide-valve engine, to 
be complete in every particular, including two pulleys, 
governor, governor belt, throttle valve, sight-feed lubri¬ 
cator, oil cups, cylinder and air bibbs and foundation 
bolts. 

1 piece 4-ply rubber belting, 7 inches in width, to connect 
engine with blower. 


Boiler 

1 15-H. P. portable locomotive boiler, “water bottom” 
type, mounted on skids, complete with grates, steam and 
water gauges, gauge cocks, whistle and pipe, safety, 
blow-off, check and stop valves, smokestack and guy 
ropes. This boiler is to be constructed for a working 
pressure of 100 lbs. to the square inch. 


115 


FRASER & CHALMERS 


Pumps, Heater and Piping 

i Duplex boiler feed pump, 2 x / 2 x i l / 2 x 2 inches. 

i Boiler feed injector. 

i Duplex steam pump, 3x2x3 in., for supplying water to 
tank. 

All necessary steam and water piping, fittings and valves for 
making connections between boiler, engine, two pumps, 
injector, heater, tank and furnace. 

Tank 

1 Round wooden water tank, 10 x 10 ft., to hold 5,100 gal¬ 
lons; to be made of 2-inch dressed lumber and bound 
with eight hoops. 

Building Bolts 

All building bolts required in the construction of a building 
to contain this machinery and to be designed by us. 

Drawings 

All drawings necessary for the erection of this machinery. 


PARTIES WHO CONTEMPLATE INSTALLING 
A REVERBERATORY OR BLAST FURNACE 
PLANT FOR SMELTING COPPER OR LEAD ORES 
OR FOR IRON MATTE SMELTING WILL FIND 
IT TO BE TO THEIR INTEREST TO WRITE TO 
FRASER & CHALMERS FOR ESTIMATES; 
THEY BUILD COMPLETE EQUIPMENTS FROM 
TEN TONS CAPACITY AND UPWARDS.*^^ 


116 


5eCT>ON THffOU^H SMELTiMg ROOM 


Suij|3iu§=j3ddo^ U BLU 9 


















































































































































































































FRASER & CHALMERS 


GENERAL SMELTING OPERATIONS 

Several years ago, when we published the first edition of 
this catalogue, the metallurgy of copper and lead in the 
United States was in its infancy, and the only literature on the 
subject available to English reading people was Dr. Percy’s 
work, “The Metallurgy of Lead'’, and Mr. Vivian’s little 
book on “ Copper Smelting” as practiced in Swansea. 

On account of this lack of information on the subject of 
general smelting operations when we all were students in the 
business, we thought it would be of some little value to our 
customers to devote a few pages to “ Advice on the Running 
of Smelting Plants”. 

Since that time, however, books have been published 
which treat the subject exhaustively and much better than 
we could do within the limited space at our disposal. 

We refer our customers who require such information to 
two most valuable metallurgical treatises: 

“The Metallurgy of Lead,” by Prof. H. O. Hofman; 

“Modern Copper Smelting,” by E. D. Peters Jr. 

In these books the smelting of lead and copper ores, 
furnace work, etc., are thoroughly described, and our 
customers will find in them all the knowledge on the subject 
obtainable from books. 


117 


FRASER & CHALMERS 




COST OF SMELTING 

In order to estimate the cost of smelting it is necessary to 
be acquainted with the character of the ores, know the per¬ 
centage of fluxes to be added to make a proper smelting mix¬ 
ture, also the cost of these fluxes, and of fuel, price of common 
and skilled labor, size of the plant, etc. If the ores require 
roasting, the cost for treatment will be considerably aug¬ 
mented. 

Roughly speaking, we may say that in large lead smelting 
plants where the ores can be made self-fluxing, the cost per 
ton of ore is about $4.50, and for ores which require con¬ 
siderable fluxing, about $7.00. 

In large copper matting plants, ore can be smelted to 
matte under favorable conditions for $3.50. It will be readily 
understood that the cost of smelting in a large furnace is 
very much less (sometimes 50%) than in a small one. 


118 


FRASER & CHALMERS 


REVERBERATORY SMELTING FURNACES 

The old English reverberatory used for matting copper 
ores, would hardly be recognized in the large modern Ameri¬ 
can furnace which is its offspring. 

This type of furnace is largely used in the United States, 
and to show the general appearance and construction of a 
very large one of the latest design, we introduce Plates 827 
and 828, which are reductions of the plan and elevation of 
one recently built by us; it has a smelting hearth 37^2 ft- 
long by 15 ft. wide, the length over all being 54 ft. The fur¬ 
nace is provided with three steel double charging hoppers for 
ore and one steel double hopper for coal; the hoppers have 
telescopic necks which are pulled down when charging, to 
prevent dust. The fire-box is provided with blast pipe; the 
ash pans are two cars resting on rails which are lifted out of 
the ash pit bodily and run out on a track to the dumping 
ground. 


FRASER & CHALMERS BUILD REVERBERA¬ 
TORY SMELTING FURNACES OF ALL SIZES 
AND DESIGNS j*jtjtj*j*j*j*j*'* 


Plate 828 


FRASER & CHALMERS 



120 


Large Reverberatory Smelting Furnace 


































































































































Plate 827 



121 


Large Reverberatory Smelting Furnace 






















































































































































































































































































































FRASER & CHALMERS 


DISPOSITION OF SLAG 

The disposition of slag in large smelting plants is a 
matter of considerable importance. If possible, the smelter site 
should be so selected as to permit of an extensive slag dump; 
when, however, such ground is not available and the furnaces 
have to be placed on level ground, the disposition of slag is 
troublesome and expensive. 

We will mention a few ways by which slag may be 
disposed of: 

1. At a certain smelter in Mexico, the molten slag is 
cast into large bricks (the work being done by natives under 
contract), and the brick used for walls, buildings, drains and, 
in fact, for any purpose for which ordinary bricks can be 
employed. The bricks are large, about the size of an 
“adobe”. 

2. Slag can be advantageously used for “plating” the 
furnace yard, thus making a hard level surface for slag pots, 
also upon which to break up matte. The plates, made of 
molten slag, are blocks 3 to 4 feet square by about 8 inches 
thick. 

3. Where water is available, slag can be granulated and 
sluiced to a distance. 

4. When a dump is available, but at some distance from 
the furnace, molten slag may be transported in a large bowl 
mounted on a four-wheel truck; upon arrival at the edge of 
the dump it is poured out. These large slag trucks are 
drawn either by animals, a locomotive, an electric motor, or 
by a wire rope. They may be filled directly from the fore¬ 
hearth, or from ordinary slag pots when it is desired to save 
slag shells, the slag being drawn from a tap-hole in the side 
of the bowl. This method is practiced at many large smelters. 


122 


FRASER & CHALMERS 




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FRASER & CHALMERS 


Plate 782 illustrates a car we have especially designed for 
this purpose. It consists of an oval bowl of 35 cubic feet ca¬ 
pacity, suspended by trunnions on two flanged wheels which 
roll on two bent rails placed at right angles to the truck. 
The truck frame is made of 5-inch steel channels supported 
on four car wheels 30 inches in diameter. At each end there 
is a platform, brake, spring buffers and connecting links for 
coupling. 

The bowl is nicely balanced, so that when full of slag 
very little power is required to tip it over. At each end there 
is a steel pin worked by a lever which, when pushed into a 
hole in the wheel supporting the bowl, holds it securely in 
position. All nuts are double. In fact nothing has been 
spared to make this car as perfect as possible. 

Plate 815 and 816 illustrate another design of car used for 
the same purpose; the bowl is round and has a capacity of 
25 cubic feet. 

5. Granulated slag may be transported to a considerable 
distance by means of an aerial tramway, a method extensively 
used in Europe. 

Plate 872 shows our arrangement of a tramway for re¬ 
moving 800 tons of slag per day from a large smelter located 
on level ground. The granulated slag is raised by an ele¬ 
vator to a storage bin from which the tramway buckets are 
loaded. 

The six small rectangles shown in the cut indicate the 
blast furnaces. 




124 


Plate 782 


FRASER & CHALMERS 




. .. a 






125 


Slag Car with Oval Bowl 

Capacity 35 cubic feet 























































































































































































































FRASER & CHALMERS 


6. It has been suggested that granulated slag be blown 
through a pipe as is u culm ”. 

7. Slag is often sold to railroad companies for ballast 
and in this way considerable profit is realized from this ma¬ 
terial. 

Considerable material, such as slag shells, furnace break¬ 
ings and matte, have to be re-smelted, and to raise this mate¬ 
rial to the feed-floor, certain machinery is required. For this 
purpose a platform elevator may be used, or an inclined rail¬ 
way called a “slag-hoist”. 

The slag-hoist comprises an inclined track which starts 
from the dump and terminates above storage bins located 
above the feed-floor; on this track runs an automatic dump¬ 
ing car drawn by wire rope operated by a belt-driven friction 
hoist. Such a railway has sufficient capacity for several 
furnaces. 


126 


918 9 ^Id 


FRASER & CHALMERS 



127 


Slag Car with Round Bowl 

Capacity 25 cubic feet. Position of bowl when slag is being poured out 














Plate 815 


FRASER & CHALMERS 



128 


Slag Car with Round Bowl 

Capacity 25 cubic feet 



























FRASER & CHALMERS 


SEPARATION OF MATTE FROM SLAG 

When a furnace is large enough to yield a continuous 
flow of slag the separation of matte from slag may be per¬ 
formed inside of the furnace by using Mathewson’s slag tap, 
which is a detachable forehearth bolted to the furnace jacket. 
By this arrangement the blast is trapped, the slag overflows 
continuously, and the matte is tapped at intervals from a 
lower level. 

Separation is made outside of the furnace in settling 
pots, which are large slag pots (see Plate 845); in forehearths 
(Plate 801); or in a reverberatory forehearth, which is a deep 
reverberatory hearth connected with a fire-box; into this 
hearth the slag and matte run directly from the furnace and 
remain there long enough for a clean separation to take place. 


129 


Plate 8 


FRASER & CHALMERS 



130 


Improved Mineral Press 



FRASER & CHALMERS 


THE BRICKING OF FINE ORE 

In a smelting plant there is always more or less flue-dust 
and fine ores to be smelted, but to charge such material 
directly into the blast furnace would cause much trouble; it 
chokes the furnace, causes irregularity, lessens its capacity, 
and sometimes it will even sift through the charge and pour 
through the tuyere openings but slightly changed. To avoid 
this evil, it is customary to mix this fine ore with clay, or 
preferably with lime, as the latter generally has a desirable 
effect in subsequent smelting; it is then molded into bricks 
which, after being dried or burnt in a kiln, can be satisfac¬ 
torily smelted similar to any lump ore. 

The best machine on the market for bricking ores, and 
one largely used, is the “Improved Briquetting Mineral Press” 
shown in Plate 833. It consists of a Chile Mill having two 
rollers 48 inches diameter by 12 inches face, each weighing 
5,000 lbs., which revolve in a pan, part of the bottom of 
which is formed by a perforated disc or diaphragm, the latter 
being made to revolve slowly. 

Fine ore, or flue-dust, mixed with the proper quantity of 
bonding material is fed into the pan; the rollers press it 
into the cylindrical openings in the revolving disc, and as 
each successive pair of molds or openings filled with solid 
briquettes (subjected to very considerable pressure under the 
ponderous rollers) pass out of the pan, they stop directly 
under the plungers of a “ re-press ” where a second or finish¬ 
ing pressure is applied; then passing on a little further, they 
are met by a pair of plungers which force them out of the 
disc and on to an endless belt. 


131 


FRASER & CHALMERS 


The complete bricking plant comprises the press, a mixer 
for preparing milk of lime, a mixer for mixing the milk of 
lime with the ore and conveying it to the press, and an auto¬ 
matic feeder. Plate 833 shows the press only. 

Bricks made with this machine are very hard and with¬ 
stand breakage even when dropped from a height of several 
feet. 

Parties contemplating the purchase of this valuable 
accessory to a smelting plant will find the following data of 
value: 

The press is 6 ft. 2 in. high over all and occupies a floor 
space 9 ft. 6 in. x 11 ft. 6 in. 

The machine should rest on a pier of masonry. 

The machine is started and stopped by means of a lever 
connected with a friction-clutch pulley. 

The capacity is 80 bricks per minute, the tonnage per 
day of ten hours varying according to the character and 
weight of the material. 

To operate the press and accessories, 35 horsepower is 
required. 

The gross shipping weight of the press and accessories is 
about 50,000 pounds. 


FRASER & CHALMERS DESIGN AND MANU¬ 
FACTURE CONCENTRATION PLANTS, CHLO¬ 
RINATION WORKS, CYANIDE MILLS ^ S S £ 


132 


FRASER & CHALMERS 





m 

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Refining 

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COPPER CONVERTING 
COPPER REFINING 
CUPELLATION 
LEAD REFINING 



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133 










FRASER & CHALMERS 


COPPER CONVERTING 


BRIEF DESCRIPTION OF THE PROCESS 

To bessemerize copper matte, which consists principally 
of copper, iron and sulphur, is to convert it into metallic 
copper by burning off its sulphur and slagging off its iron 
contents. 

The process is conducted in a steel vessel called a con¬ 
verter, similar to that used for making bessemer steel. The 
converter has a thick lining of crushed quartz mixed with a 
sufficient quantity of clay to hold the quartz together; near 
the bottom of the converter is attached a wind-box which 
supplies air to a number of horizontal tuyeres, these being 
simply holes pierced through the lining. Molten copper 
matte is charged into the converter in quantity equal to its 
capacity (from 3 to 10 tons), and air from a blowing engine 
under a pressure of from 6 to 15 lbs. is forced through the 
molten mass. The sulphur combines with the oxygen of 
the air forming sulphurous acid gas, which passes off while 
the iron is oxidized and unites with the quartz of the lining 
to form a slag; the slag is poured or skimmed off and returned 
to the blast furnace, and the metallic copper is poured out 
into molds. No fuel is used in this operation, the heat 
being supplied by the combustion of the sulphur in the 
matte. 

Usually, mattes are not bessemerized which contain less 
than 45 percent, copper, and they are “blown” to blister 
copper in one operation. 

Lower grade mattes corrode the lining too rapidly, and 
high grade mattes (60 per cent, and higher) do not furnish 
sufficient heat by their oxidation. 


134 


FRASER & CHALMERS 


The following typical figures taken from “ Modern Cop¬ 
per Smelting 1 ’ serve to illustrate the composition of the 


matte, slag, copper, etc.: 

Slag 

Produced. 

Matte. 

1. 

2. 

Copper, . . 51 per cent. 

Silica, .... 41.90 

3570 

Iron, ... 22 “ 

Ferrous oxide, 48.06 

55-83 

Sulphur, .26 u 

Copper, ... 1.00 

2.00 


Blister copper produced, 99 per cent. 


Converter Lining. 


For Body 
or Shell. 


Parts by volume - 


f Clay,.17 

\ Quartz, .... 83 


For Top. 
28 
72 


IOO IOO 


From the above figures, it will be seen that the lining is 
rapidly eaten out, in fact that the operation is performed at 
the expense of the lining, and that the process differs very 
materially from the bessetner process as applied to steel 
making, the former requiring 50 per cent, of its contents to 
become oxidized, while the latter requires from 3 to 5 per 
cent. 

Bessemerizing copper mattes was first practiced in the 
United States in 1884, since which time we have been large 
builders of converting machinery, having furnished such 
machinery to the Anaconda Smelting Works, Copper Queen, 
United Verde, Nichols Chemical Co., Arizona Copper Co., 
Mount Lyell Mining & Railway Co. of Tasmania, and others. 


PARTIES WHO CONTEMPLATE PURCHASING 
PUMPS, AIR COMPRESSORS OR BLOWING 
ENGINES SHOULD NOT FAIL TO INVESTI¬ 
GATE THE ** RIEDLER,” WHICH IN EFFI¬ 
CIENCY, ECONOMY AND DURABILITY ARE 
UNEQUALED. 


135 








FRASER & CHARMERS 


COPPER=CONVERTING MACHINERY 

CONVERTERS 

Copper converters are of different shapes and sizes, 
though in general appearance they are more or less similar 
to the vessel used for bessemerizing iron. They may be 
divided into three types: The round or “Parrot” converter, 
Fig. 788, used by the Anaconda Co. and others; the square 
or “Stalmann” converter, Fig. 787, used by the Mt. Ryell 
Mining & Railway Company of Tasmania, the Mazapil 
Copper Company of Mexico and others, and the trough or 
“Bisbee” converter, Fig. 785, used by the Copper Queen 
Mining Company, Arizona Copper Company and others. 

Converter shells are made of heavy steel plates riveted 
together. They are supported either on trunnions or rollers, 
and are tilted by hydraulic machinery. For convenience in 
re-lining, the top is separable from the body, and in the 
Parrot the shell is separable into four sections. 

The capacity of converters may vary from 3 to 10 tons, 
the capacity of a newly lined converter being less than it is 
after several “blows”, as the lining is being continually eaten 
away. 

The following table taken from “Modern Copper Smelt¬ 
ing” gives details of the size, capacity, etc., of different 
converters: 


COMPANY. 

Outside 

Height, 

feet. 

Outside 

Diameter, 

feet. 

Blast 
Preserve, 
lbs. per 
sq.in. 

Initial 
Charge, 
lbs. 

Maximum 
Charge, 
lbs. 

Blows per 
24 hrs. 

Weight of 
Shell and 
Lining. 

Number of 
Tuyeres 

Parrot & Montana Ore 
Purchasing Companies. 

8-5 

5 

II 

2500 

9000 

l6 

16000 

l6 

New Anaconda. 

IO 

6 

13 

7000 

17000 

12 

22000 

l6 

Great Falls. 

13 

7 

l6 

IOOOO 

22000 

IO 

26000 

18 

Stalmann. 

8 

5 

IO 

3 OOO 

9COO 

14 

17000 

IO 

Copper Queen. 

17 25 

5.67x8 

5-5 

4000 

I OOOO 

12 


II 


136 



























FRASER & CHALMERS 


Plate 788 



The Parrot Converter 

Round Type used by Anaconda Co. and others 


137 






FRASER & CHALMERS 



Plate 787 


The Stalmann Converter 


Square Type used by 


Mt. Lyell Mining & Railway Co. and others 


138 














Plate 829 


FRASER & CHALMERS 




139 


Small Cylindrical Converter 



































































































































































































































































FRASER & CHALMERS 


Plate 786 


The Bisbee Converter 

Cylindrical Type used by Copper Queen Mining Co. and others 

140 







FRASER & CHALMERS 


THE BISBEE CONVERTER 

The mechanism for tilting the converter consists of a ver¬ 
tical rack (Plate 786) or horizontal rack (shown in Plate 787), 
operated by a hydraulic cylinder, this rack engaginga pinion 
centered with the axis of the converter. 

The cylindrical or Leghorn type of converter is the most 
popular. The advantage of the trough or cylindrical shape is 
that when slowly tilting the converter during “blowing, ” air is 
made to pass through the upper layer of copper matte without 
disturbing the reduced copper below it, which requires 110 fur¬ 
ther action of the air. The depth of material being less than 
in the other types of converters less blast pressure is required. 

This converter is supported in the best manner to reduce 
friction to a minimum, viz., on four friction rollers on which 
two steel riding rings, which partly encompass the cylinder, 
bear. The rack being vertical leaves the space around the 
converter clear. Such satisfactory results are obtained with 
this style of converter that it is being almost universally 
adopted. 

EXPERIMENTAL CONVERTER 

For experimental purposes we manufacture a small 
“trough” converter mounted on a car, with hand-tilting 
mechanism; the capacity of this converter is from ^ to 1 % 
tons. Plate 829 shows its general appearance. 

HYDRAULIC MACHINERY 

In converting plants, hydraulic power may be used for 
tilting converters, for operating cars used for transferring 
converter shells to and from the re-lining station, and for 
operating the truck which carries the ingot molds into which 
blister copper is poured after the charge has been “blown.” 

In large plants an electric traveling crane has taken the 
place of the hydraulic transfer car. 

For tilting converters, a water pressure from 175 to 500 
pounds is used. When local conditions permit, the simplest 


141 


FRASER & CHALMERS 


method for obtaining this pressure is by pumping water into 
a tank placed considerably higher than the “bessemer pit”, 
and letting the water flow back by gravity to the hydraulic 
mechanism. This method is especially applicable where the 
cylindrical converter is used, as a height of about 400 feet 
will give a pressure of 175 pounds, which is sufficient for 
tilting this converter. 

A second method for obtaining hydraulic pressure, is by 
using an accumulator into which water is pumped under high 
pressure by a pressure pump. The accumulator is a vertical 
cylinder provided with a weighted piston. This apparatus is 
shown in Plate 784, which is a photo-engraving of one sold 
to the Mt. Lyell Mining & Railway Company of Tasmania. 

The pressure obtained with this apparatus is regular and 
uniform, and no jerking motion is imparted to the converter 
while it is turning. A governor attached to the pump, stops 
it when the piston has reached its maximum height. 

Plate 778 shows apparatus used for obtaining hydraulic 
pressure by a third and cheaper method, viz., a closed steel 
tank placed over an open steel tank, together with the neces¬ 
sary high pressure pump. The closed tank is provided with 
pressure gauge and pop safety valve, and the pump with an 
automatic speed regulator, which adjusts the speed of the 
pump to the pressure required. 

ELECTRIC CRANE 

For moving converter shells from their hydraulic stands 
to the re-lining station, either an electric traveling crane or a 
hydraulic transfer car is employed. When the finances of 
the company permit, the crane is used, as by this means all 
the lifting and transferring operations of a bessemer plant 
other than the tilting of the converters can be effected. The 
crane is provided with three independent motors—one for 
each movement and sometimes with an additional motor for 
tilting the ladle. 


142 


FRASER & CHALMERS 



143 



















FRASER & CHALMERS 



144 


Pressure Tank and Accessories 








































































































































































































































FRASER & CHALMERS 


HYDRAULIC TRANSFER CAR 

Plate 802 shows a hydraulic transfer car which is simply 
a hydraulic jack mounted on a four-wheel truck which runs 
on rails. By means of such a car with proper tracks and 
turn-tables the converter shells can be moved to any part ot 
the building. Plate 785 (page 147) shows a converter shell, 
transfer car and turn-table. 

We sometimes furnish these cars with a hand pump 
attached to the carriage, which makes the apparatus inde¬ 
pendent of outside pipe connections. 

ELECTRO-HYDRAULIC TRANSFER CAR 

A car with its load weighs some 18 to 20 tons and is 
moved slowly and with difficulty. For use where electric 
power is available, we have designed a car which is propelled 
by a motor attached to the truck, the current being taken 
from an overhead wire. 

INGOT MOLD TRUCKS 

These trucks are platforms which hold the molds when 
they are pushed under the converter to receive the blister 
copper; they are made of steel beams supported on four 
wheels which run on the same track as the transfer car, when 
the latter is used. Plate 783 (page 148) shows such a carriage, 
the top of which is made in steps so as to preserve the same 
distance between the molds and the lip for the converter 
when the converter is being poured, this being done to prevent 
splashing of the copper. 

Plate 780 shows another design of an ingot mold truck 
moved by a hydraulic cylinder placed beneath the floor; we 
have recently furnished this type to the Arizona Copper Com¬ 
pany, who find them very effective, they being much quicker, 
more adjustable, and saving hand labor to a greater extent than 
the ordinary truck. 


145 


/i 


FRASER & CHALMERS 


Plate 802 



Hydraulic Transfer Car for Moving Converters 


146 







FRASER & CHALMERS 


Plate 785 



Hydraulic Transfer Car and Turn=table for Bisbee Converter 


I 47 







Plate 783 


FRASER & CHALMERS 





I 48 


Ingot Mold Truck 







FRASER & CHALMERS 



149 























































































































Plate 7S9 


FRASER & CHALMERS 



150 


Chilian Mill for Grinding Clay for Lining Converters 







FRASER & CHALMERS 


BLOWING ENGINES 

The cost of producing the blast is a very considerable 
item in bessemerizing matte, and to reduce this expense to a 
minimum an economical blowing engine should be used. 
For descriptions of blowing engines operated by steam, water¬ 
power or electricity, best suited for delivering air under pres¬ 
sure for “blowing” converters we refer you to our Riedler 
catalogue. 

TRANSFERRING MATTE TO THE CONVERTER 

In plants where the production of matte is large, the 
blast-furnaces are provided with large forehearths in which 
several tons of matte are allowed to accumulate. The quan¬ 
tity required for a converter charge is tapped from the foie- 
hearth into a ladle, which is then carried by an electric crane 
directly to the mouth of the converter, into which it is poured. 
In smaller plants a reverberatory furnace, or reverberatory 
forehearth located near the converters, is used, in which to store 
molten matte until it is required. When a converter charge 
is needed, it is tapped directly into the converter, or into a 
ladle. Cold matte may be melted in such a reverberatory or 
in a cupola, provided with a large movable well or crucible 
mounted on wheels. 

CHILIAN MILL OR MORTAR MIXER 

Fig. 789 shows the Chilian Mill or Mortar Mixer, which 
we have designed especially for grinding the material used 
for lining converters. It consists of a shallow iron pan in 
which are placed two heavy rollers supported in a self-con¬ 
tained cast-iron frame. The pan revolves while the rollers 
are held in a fixed position. The apparatus is so constructed 
that all the wearing parts—the-pan die, roller shells and roller 
bearings—can be readily replaced when worn. 


Plate 777a 


FRASER & CHALMERS 



152 


Plant for Bessemerizing Copper Mattes 

Elevation 




































































































































































Plate 777b 


FRASER & CHALMERS 




Plant for Bessemerizing Copper Mattes 

Plan 




















































































































































































































































FRASER & CHALMERS 


CONVERTING PLANTS 

An illustration of a typical modern copper-converting 
plant is shown by Plates 777a and 777b, which are plan and 
elevation of a plant we recently built for the Arizona 
Copper Co. Ltd. 

Everything about the plant is arranged for convenience 
and economy. The buildings are of steel construction and 
well ventilated. The converters, of which there are two 
“stands”, are of the cylindrical or “Bisbee” pattern, and have 
a capacity of about five tons each. Handling of the con¬ 
verters is done by means of a 30-ton electric traveling crane. 
The matte is tapped from a reverberatory furnace into a ladle 
which rests on a 4-wheel truck ; when the ladle is full, it is 
moved by a windlass to within reach of the crane, which 
then picks it up and pours the matte into either of the 
two converters. The ingot mold carriages are moved by 
hydraulic mechanism. The blowing engine is of the Riedler 
type, driven by four gas engines. The electric crane is oper¬ 
ated from a central station on the floor of the bessemer-pit, 
so that the man in charge is not subjected to the fumes. 
Hydraulic pressure is obtained from a tank on the hill-side. 

Engineers who have visited this plant consider it a model 
one, of which the Arizona Copper Company as the owners, 
and we as the builders, may justly feel proud. 


SOME OF FRASER & CHALMERS SPECIALTIES 
ARE COMET CRUSHERS, HIGH SPEED ROLLS, 
FRUE VANNERS. 


154 


FRASER & CHALMERS 


COPPER REFINING 

Crude copper obtained by smelting oxides and roasted sul¬ 
phides in the blast furnace, or in the reverberatory, and blister 
copper from bessemerizing matte, contain from i to 3 per 
cent, of impurities (principally surphur, arsenic, etc.) which 
unfits them for commercial purposes. This impure copper is 
refined by subjecting it first to oxidation and afterwards to 
reduction in a reverberatory furnace, the method being known 
as the ordinary “Swansea” process. 

The furnace used for this purpose is strongly built and 
thoroughly bound together; below the skimming door, which 
is at the chimney end, there is a heavy cast-iron plate; some¬ 
times the entire bottom and sides of the furnace are incased 
in cast-iron plates. 

Plate 840 shows the general appearance and construction 
of H. L. Bridgman’s refining furnace, which is the outgrowth 
of his many years of practical experience in copper refining. 
We usually build this furnace to have a capacity of about 10 
tons of copper. In strength and durability it is unsurpassed. 

Formerly, refining furnaces were made to have a capacity 
of about 7 tons, but now in large plants they are sometimes 
made to hold as much as 15 tons. 

The hearth of the refining furnace is made of white sand, 
carefully smelted in and saturated with copper to make a 
“bottom”. 

Wood is the best fuel, bituminous coal being secondary; 
coals containing sulphur should not be used. 


155 


FRASER & CHALMERS 


Copper refining is a delicate operation requiring skilled 
labor. In ordinary cases the process takes 24 hours, the 
latter part of the operation being very laborious. 

The process is for refining copper which already contains 
as much as 96 per cent, of copper; copper of lower grade 
being best subjected to a preliminary melting down with free 
admission of air in a blister furnace, which is of similar con¬ 
struction to the refinery, and then tapped out into pigs which 
will then be of suitable grade for refining. 

The process of refining which comprises two stages—oxi¬ 
dation and reduction—may be briefly described as follows : 
The furnace being hot, ingots or bars of blister copper are 
charged through the side door by means of an iron paddle, 
the copper being piled up and distributed over the entire 
hearth. After charging, the fire is not strongly urged and 
air is admitted so that, as the ingots slowly melt down, oxi¬ 
dation will take place. After the copper is melted down it is 
skimmed free from slag. 

The charge boils constantly owing to the escape of anhy¬ 
drous sulphuric acid, which stirs up the molten mass even 
better than rabbling would, causing fresh surfaces to be pre¬ 
sented for oxidation ; suboxide of copper forms and exerts a 
powerful action upon the elements (chiefly metalloids), which 
exist in the copper as impurities and which have a greater 
affinity for oxygen than for copper. 

Ebullition gradually ceases owing to the disappearance of 
most of the sulphur, and suboxide of copper then rapidly 
forms. 


156 


FRASER & CHALMERS 


Sulphur clings to copper with great tenacity ; to elimi¬ 
nate the small quantity which still remains, flapping or 
rabbling the charge is resorted to, in order to constantly ex¬ 
pose fresh portions to oxidation. 

Finally, by the slow and tedious operation of rabbling and 
skimming, the injurious impurities are oxidized and removed 
either in the slag, or by volatilization. When this point (which 
is determined by physical examination of small test samples) 
has been reached, the oxidation stage is concluded. 

We now have a bath of commercially pure copper, con¬ 
taining considerable suboxide; to convert the latter into 
metallic copper, reduction must be resorted to. This is 
effected by covering the surface with charcoal and burying a 
long pole of green wood in the molten copper; large vol¬ 
umes of hydrocarbons and other reducing gases are thus 
evolved, which rapidly remove the excess of oxygen. This 
process is termed “poling”. 

When all the suboxide has been reduced, test samples 
taken from the furnace show a fibrous texture and silky lustre 
of a rose-red color, and the sample ingot does not contract on 
cooling, that is, the top remains flat. The copper is then 
said to have reached its “ pitch”, and is ready for ladling. 

Ladling is done as rapidly as possible, so as not to give 
the copper time to change its pitch; the fire should be pre¬ 
viously attended to and everything arranged so that during 
ladling there will be an equally balanced oscillation between 
oxidizing and reducing action in the furnace. 


157 


FRASER & CHALMERS 


It takes very little to throw copper out of pitch, and any 
change is immediately shown by the appearance of the ingots. 
If on cooling, the ingots contract, leaving a depression in the 
center, it indicates that suboxide is forming, and ladling 
must be stopped and the charge poled a little; short sticks of 
green wood thrown on top of the copper assist in the reduc¬ 
tion. If, on the other hand, the surface of the ingot rises and 
becomes convex, then the charcoal must be pushed back from 
the ladling door, and the charge flapped or rabbled. It only 
takes a few moments to bring the copper back to its proper 
pitch, and it is here that skilled labor is indispensable. 

Ladling is usually performed by four men, two loading 
while the other two are resting. 

If the copper contains neither gold nor silver, it is cast into 
ingots weighing about 16 lbs. The molds are made of 
copper and are arranged on a shaft fastened to a bosh con¬ 
taining water, so that upon being tipped upside down, the ingot 
falls out and drops into the water; this is done to give the 
ingot a red copper color which is due to a thin coating of 
suboxide. 

Should the copper contain gold or silver, it is cast into 
rectangular plates weighing some 200 lbs., called anodes, 
which are of convenient size for the electrolytic refinery. 


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158 


FRASER & CHALMERS 


Plate 840 



Copper=Refining Furnace 

H. L. Bridgman’s Design 


159 






































































































































































































FRASER & CHALMERS 


CUPELLATION 

Lead melted with free access of air is oxidized to litharge, 
while silver and gold, should any be any present, remain un¬ 
changed. Advantage is taken of this fact, to separate gold 
and silver from lead and other base metals, the process being 
called “ cupellation”. 

The operation is conducted in a reverberatory furnace. 
The oxidation of the lead is accelerated by a blast of air made 
to play over its surface, the litharge being allowed to flow off 
as fast as formed, thus permitting afresh surface of lead to be 
continually presented for oxidation. The operation is con¬ 
tinued until all the lead has been converted into litharge and 
removed; the remaining contents of the hearth being a 
molten mass of refined silver or dore bullion. 

The operation may take several hours, fresh bars of ar¬ 
gentiferous lead being added from time to time. The silver 
remaining in the test at the conclusion of the operation may 
amount to several thousand ounces. 

In a lead refinery where there is much lead to be cupelled, 
the silver-lead bars from the retorts are first concentrated by 
cupelling off a large percentage of the lead in a large (usually 
water-jacketed) cupel furnace, called a “concentrator”, and 
the rich silver-lead thus obtained is afterwards completely 
cupelled in a smaller cupel furnace. 

Plate 858 (page 164) shows a welded steel jacket for a 
concentrator test. 

The cupel furnace is sometimes used for extracting silver 
and gold from lead bullion obtained from the blast furnace, 
the litharge being afterwards reduced with coke in the blast 
furnace. 

In leaching works where silver is extracted from the ore 
by sodium hyposulphite and precipitated as sulphide, the 
best method for refining the sulphide is to cupel it with lead, 
fine silver bars being the resultant product. 


160 


FRASER & CHALMERS 


Jewelers’ sweepings, rich residues, etc., are usually refined 
by smelting them with lead and cupelling the base bullion 
produced. 

The English cupelling furnace is the one used for the 
work herein mentioned. 

Plate 65 shows our double English cupelling furnace. 
It consists of a removable reverberatory hearth placed 
between a fire-box and a flue, all being contained in a brick 
structure. The hearth comprises an iron frame called a 
“test bottom”, which is filled with a mixture of ground 
limestone and fire-clay. The test bottom is supported on a 
car, by means of which it can be readily removed and 
another bottom substituted in its place. Pipes connected 
with a fan conduct a blast to the fire-box and to the lead 
bath. 

The outfit for a double English cupelling furnace as 
furnished by us comprises: 

2 Fire and Ashpit Doors and Frames. 

2 Litharge Doors and Frames. 

2 Charging Doors and Frames. 

2 sets of Grate Bars and Bearers. 

2 Bottom Plates. 

1 double set of Wall Binders and Tie Rods. 

2 Litharge Pots and Cars (see Plate 66). 

2 Test Cars (see Plate 66). 

2 Test Bottoms. 

4 extra Test Bottoms. 

4 pieces of Track for Test Cars. 

4 Tuyere Nozzles (two for cupelling and two for fire blast). 

1 double set of Galvanized Iron Blast Pipe, with regu¬ 
lating valves and nozzles for tuyeres, ready for connecting to 
pipe leading from Blower. 

Total weight, 8,300 lbs. 

The smokestack is always considered separately, as in 
many cases the brick stack is preferred. 


161 


Plate 65 


FRASER & CHALMERS 



162 


Double English Cupelling Furnace 


































































































































































































































































































FRASER & CHALMERS 


Plate 877 




English Cupelling Furnace 

With Arrangement for Raising or Lowering the Test 


163 









































































































































































































































































































FRASER & CHALMERS 


Plate 858 



WELDED STEEL WATER JACKET FOR A CUPEL TEST 


The double furnace requires 16,000 common brick, 2,800 
fire-brick and four barrels of fire-clay. 

The single furnace requires 9,000 common brick, 1,400 fire¬ 
brick, and two barrels of fire-clay. 

Plate 877 shows an English cupelling furnace in plan 
and elevation, with an arrangement for raising and lowering 
the test, to regulate the flow of litharge without altering the 
depth of the litharge gutter. 


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164 



FRASER & CHALMERS 


LEAD REFINING 

Lead refining or the desilverization of base bullion, is the 
process of separating the precious metals from lead bars 
obtained by smelting gold, silver and lead ores. For 
accomplishing this, the processes of Pattinson and Parkes are 
available. 

The Pattinson process is based upon the fact that if silver- 
lead bullion is melted and then cooled down to near its 
fusing point, crystals of lead separate out which are very 
much poorer in silver than the original lead. If, at this 
stage, these crystals are removed by a strainer and fresh lead 
of the same tenor in silver added, the heat increased, the 
lead stirred and then allowed to cool down as in the first in¬ 
stance, crystals of lead, poor in silver, will again separate out. 

By continuing these operations practically all the silver 
and gold in the bullion will become concentrated in a small 
quantity of lead which can afterwards be cupelled. 

The Pattinson process is not used in the United States. 

Parkes’ process, universally used in the United States, is 
based upon the fact that if a very small percentage of metallic 
zinc is stirred into a bath of molten lead which contains gold 
and silver, and the lead then allowed to cool down somewhat, 
the zinc will deprive the lead of the precious metals, forming 
an alloy which, being less fusible and of lower specific gravity 
than the lead, will rise to the surface and can be skimmed 
off and afterwards treated separately for the separation of the 
gold and silver contents. 

The process, which consists of several operations, may be 
briefly described as follows: 

The smelter lead is first put into a reverberatory furnace 
known as a “softener,” where it is subjected for some con¬ 
siderable time at a low heat to the process of liquation, 
whereby there will arise to the surface dark colored pasty 
dross, consisting of lead, copper, arsenic and sulphur, which 
is skimmed off The slower this operation is performed the 
more perfect will be the elimination of the copper. 


165 


FRASER & CHALMERS 


After this stage of the operation has been concluded, the 
heat is raised and free access of air admitted, whereby com¬ 
plete oxidation of tin, arsenic and antimony takes place, 
these impurities being also removed by skimming. Of all 
the impurities in lead bullion, antimony is the most difficult 
to remove. 

Lead thus purified is ready for the desilverizing kettle; 
this is a large cast-iron kettle, sometimes holding as inuctfi 
as 60 tons of lead, placed on a brick setting provided with a 
fire-place. In this kettle usually three “ zincings ” are made; 
the first extracts all the copper, all the gold and considerable 
of the silver (the skimmings being called the “gold crust”), 
the second (the “ silver crust ”) reduces the silver to some 
30 ounces per ton ; the third, usually the last, cleans the lead 
down to less than 0.2 ounces silver and generally only a trace. 

The zinc crusts are next placed in a liquating kettle 
which is a shallow cast-iron kettle provided with a discharge 
spout which drains the bottom. The zinc crusts heated in 
this kettle lose from 50 to 60 per cent, of lead by liquation, 
this lead running out into a smaller kettle placed on a lower 
level, leaving the dry zinc crusts behind. This liquated lead, 
which contains silver and gold, is returned to the desilver¬ 
izing kettles. 

The liquated zinc crusts are next retorted in a bottle¬ 
shaped black lead retort, placed in a “Faber du Faur ” furnace, 
each furnace being made to hold one retort. The fuel, which 
is usually coke, surrounds the retort. By this process, the 
zinc is distilled off; the greater part recovered in the metallic 
state is used for “zincing”. When no more zinc comes off, 
the rich lead bullion is poured into molds by tilting the furnace, 
which is supported on trunnions. 

The rich lead is cupelled; the rough bars of fine gold and 
silver from the cupel are remelted and cast into fine silver or 
dore bars, the latter being subsequently treated by the electro¬ 
lytic, or wet methods, for the separation of the gold and silver. 

166 


FRASER & CHALMERS 

Plate 878 

j 








Lead Refinery 











































































































































































































FRASER & CHALMERS 


The lead in the desilverizing kettles, after having been 
freed from gold and silver, contains a certain percentage of 
zinc which must be removed. To effect this separation, it is 
syphoned into a refining furnace (a reverberatory similar to a 
“softener”); here under the action of heat and oxidation, the 
zinc is partly volatilized, partly oxidized and scorified by the 
litharge, and is removed by skimming. 

After tests have shown that the zinc has been eliminated, 
the lead is tapped into the “merchant” kettle, and from this 
it is syphoned out into bars, which constitute the pig lead of 
commerce. 

The several by-products of the refinery, the drosses from 
the softening and refining furnaces, the litharge from cupel- 
lation and the blow-powder from the retorts, are all treated 
by different processes; the constant treatment of by-products 
goes on simultaneously with the desilverization of the lead 
bullion. 

Plate 878 illustrates the general arrangement of a modern 
refinery, the details of which will be understood from what 
we have written. The two softening furnaces will be recog¬ 
nized, also the two groups of desilverizing and liquating ket¬ 
tles, the two refining furnaces, and the merchant kettles with 
the molds arranged in a semi-circle for casting the lead into 
merchant pigs. In the smaller room are shown six “Faber 
du Faur” retorts and two double cupel furnaces. 



168 


Fraser & Chalmers’ Catalogues 


English Editions in Order of Numbers 


1. Engines and Boilers. 

2. Haulage and Hoisting Machinery. 

3. Smelting Furnaces. 

4. Gold and Silver Mills. 

6. Comet Crushers. 

7. Perforated Metal. 

8. Crushers and Pulverizers. 

9. Concentration Machinery. 

10. Huntington Mills. 

12. Corliss Engines. 

13. Frue Vanners. 

15. Wire Cloth. 

16. Automatic Ore Feeders for Stamps, 

Rolls, and Huntington Mills. 

17. Ore Cars, Anaconda Wheels and 

Axles. 

18. Boss’ Continuous System, Pan Amal¬ 

gamation. 

19. Pelton Water Wheels. 


20. Bruckner Furnaces. 

22. Cornish Pumping Engines. 

23. Machinery for Patio Process. 

24. Riedler Pumping Engines. 

25. Assay Outfit. 

28. Gold Milling in the Black Hills. 

29. Losses in Gold Amalgamation. 

30. Knowles Pumps. 

31. Blake Pumps. 

32. Bridgman’s Patent Ore-Sampling 

Machines. 

33. Leffel Water Wheels. 

34. Green Blowers. 

46. Riedler Air Compressors. 

P. 3. Adams Boilers. 

51. Woods’ Dry Placer Miner. 

52. Ball Pulverisers. 

54. Sederholm Boilers. 


Spanish Editions of Numbers 1, 3, 4, 12, 30, 31, 33. 
French Editions of Numbers 1, 3, 4, 7, 12 , 26. 


We also issue numerous special circulars. Correspondents 
favoring us with inquiries are reminded that the fullest data 
practicable, explaining their requirements, will help us 
greatly to meet them and supply information in the most 
definite and useful form. 


Press of 

Hollister Brothers 
Chicago 







